Medicines Data Repository Implementation Guide
0.1.0 - ci-build

Medicines Data Repository Implementation Guide, published by Te Whatu Ora. This guide is not an authorized publication; it is the continuous build for version 0.1.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7NZ/mdr/ and changes regularly. See the Directory of published versions

Resource Profile: ObservationBodyweight - Detailed Descriptions

Page standards status: Trial-use Maturity Level: 5

Definitions for the bodyweight resource profile.

Guidance on how to interpret the contents of this table can be found here

0. Observation
Definition

This profile defines how to represent body weight observations in FHIR using a standard LOINC code and UCUM units of measure.

ShortFHIR Body Weight Profile
2. Observation.code
Definition

Body Weight.

ShortBody Weight
Comments

additional codes that translate or map to this code are allowed. For example a more granular LOINC code or code that is used locally in a system.

Alternate NamesTest, Name
4. Observation.code.coding
Control1..?
SlicingThis element introduces a set of slices on Observation.code.coding. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ code
  • value @ system
  • 6. Observation.code.coding:BodyWeightCode
    Slice NameBodyWeightCode
    Control1..1
    8. Observation.code.coding:BodyWeightCode.system
    Control1..?
    Fixed Valuehttp://loinc.org
    10. Observation.code.coding:BodyWeightCode.code
    Control1..?
    Fixed Value29463-7
    12. Observation.value[x]
    [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
    SlicingThis element introduces a set of slices on Observation.value[x]. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • type @ $this
    • 14. Observation.value[x]:valueQuantity
      Slice NamevalueQuantity
      Control0..1
      TypeQuantity
      [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
      16. Observation.value[x]:valueQuantity.value
      Control1..?
      Must Supporttrue
      18. Observation.value[x]:valueQuantity.unit
      Control1..?
      Must Supporttrue
      20. Observation.value[x]:valueQuantity.system
      Control1..?
      Must Supporttrue
      Fixed Valuehttp://unitsofmeasure.org
      22. Observation.value[x]:valueQuantity.code
      Definition

      Coded responses from the common UCUM units for vital signs value set.

      ShortCoded responses from the common UCUM units for vital signs value set.
      Control1..?
      BindingThe codes SHALL be taken from BodyWeightUnits
      (required to http://hl7.org/fhir/ValueSet/ucum-bodyweight|4.0.1)

      Common UCUM units for Body Weight.

      Must Supporttrue

      Guidance on how to interpret the contents of this table can be found here

      0. Observation
      Definition

      This profile defines how to represent body weight observations in FHIR using a standard LOINC code and UCUM units of measure.


      Measurements and simple assertions made about a patient, device or other subject.

      ShortFHIR Body Weight ProfileMeasurements and simple assertions
      Comments

      Used for simple observations such as device measurements, laboratory atomic results, vital signs, height, weight, smoking status, comments, etc. Other resources are used to provide context for observations such as laboratory reports, etc.

      Control0..*
      Is Modifierfalse
      Summaryfalse
      Alternate NamesVital Signs, Measurement, Results, Tests
      Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
      dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
      dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
      dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
      dom-6: A resource should have narrative for robust management (text.`div`.exists())
      obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present (dataAbsentReason.empty() or value.empty())
      obs-7: If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present (value.empty() or component.code.where(coding.intersect(%resource.code.coding).exists()).empty())
      vs-2: If there is no component or hasMember element then either a value[x] or a data absent reason must be present. ((component.empty() and hasMember.empty()) implies (dataAbsentReason.exists() or value.exists()))
      obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present (dataAbsentReason.empty() or value.empty())
      obs-7: If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present (value.empty() or component.code.where(coding.intersect(%resource.code.coding).exists()).empty())
      2. Observation.implicitRules
      Definition

      A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

      ShortA set of rules under which this content was created
      Comments

      Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

      Control0..1
      Typeuri
      Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      4. Observation.modifierExtension
      Definition

      May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

      Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

      ShortExtensions that cannot be ignored
      Comments

      There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

      Control0..*
      TypeExtension
      Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
      Summaryfalse
      Requirements

      Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.


      Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

      Alternate Namesextensions, user content
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      6. Observation.status
      Definition

      The status of the result value.

      Shortregistered | preliminary | final | amended +
      Comments

      This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

      Control1..1
      BindingThe codes SHALL be taken from ObservationStatushttp://hl7.org/fhir/ValueSet/observation-status|4.0.1
      (required to http://hl7.org/fhir/ValueSet/observation-status|4.0.1)
      Typecode
      Is Modifiertrue because This element is labeled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Must Supporttrue
      Summarytrue
      Requirements

      Need to track the status of individual results. Some results are finalized before the whole report is finalized.

      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      8. Observation.category
      Definition

      A code that classifies the general type of observation being made.

      ShortClassification of type of observation
      Comments

      In addition to the required category valueset, this element allows various categorization schemes based on the owner’s definition of the category and effectively multiple categories can be used at once. The level of granularity is defined by the category concepts in the value set.

      Control10..*
      BindingThe codes SHOULD be taken from ObservationCategoryCodeshttp://hl7.org/fhir/ValueSet/observation-category
      (preferred to http://hl7.org/fhir/ValueSet/observation-category)

      Codes for high level observation categories.

      TypeCodeableConcept
      Is Modifierfalse
      Must Supporttrue
      Summaryfalse
      Requirements

      Used for filtering what observations are retrieved and displayed.

      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      SlicingThis element introduces a set of slices on Observation.category. The slices areUnordered and Open, and can be differentiated using the following discriminators:
      • value @ coding.code
      • value @ coding.system
      • 10. Observation.category:VSCat
        Slice NameVSCat
        Definition

        A code that classifies the general type of observation being made.

        ShortClassification of type of observation
        Comments

        In addition to the required category valueset, this element allows various categorization schemes based on the owner’s definition of the category and effectively multiple categories can be used at once. The level of granularity is defined by the category concepts in the value set.

        Control10..1*
        BindingThe codes SHOULD be taken from ObservationCategoryCodeshttp://hl7.org/fhir/ValueSet/observation-category
        (preferred to http://hl7.org/fhir/ValueSet/observation-category)

        Codes for high level observation categories.

        TypeCodeableConcept
        Is Modifierfalse
        Must Supporttrue
        Summaryfalse
        Requirements

        Used for filtering what observations are retrieved and displayed.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        12. Observation.category:VSCat.coding
        Definition

        A reference to a code defined by a terminology system.

        ShortCode defined by a terminology system
        Comments

        Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

        Control10..*
        TypeCoding
        Is Modifierfalse
        Must Supporttrue
        Summarytrue
        Requirements

        Allows for alternative encodings within a code system, and translations to other code systems.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        14. Observation.category:VSCat.coding.system
        Definition

        The identification of the code system that defines the meaning of the symbol in the code.

        ShortIdentity of the terminology system
        Comments

        The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

        Control10..1
        Typeuri
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supporttrue
        Summarytrue
        Requirements

        Need to be unambiguous about the source of the definition of the symbol.

        Fixed Valuehttp://terminology.hl7.org/CodeSystem/observation-category
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        16. Observation.category:VSCat.coding.code
        Definition

        A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

        ShortSymbol in syntax defined by the system
        Control10..1
        Typecode
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supporttrue
        Summarytrue
        Requirements

        Need to refer to a particular code in the system.

        Fixed Valuevital-signs
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        18. Observation.code
        Definition

        Body Weight.


        Describes what was observed. Sometimes this is called the observation "name".

        ShortBody WeightType of observation (code / type)
        Comments

        additional codes that translate or map to this code are allowed. For example a more granular LOINC code or code that is used locally in a system.


        All code-value and, if present, component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

        Control1..1
        BindingUnless not suitable, these codes SHALL be taken from For example codes, see VitalSignshttp://hl7.org/fhir/ValueSet/observation-codes
        (extensible to http://hl7.org/fhir/ValueSet/observation-vitalsignresult)

        This identifies the vital sign result type.


        Codes identifying names of simple observations.

        TypeCodeableConcept
        Is Modifierfalse
        Must Supporttrue
        Summarytrue
        Requirements
        1. SHALL contain exactly one [1..1] code, where the @code SHOULD be selected from ValueSet HITSP Vital Sign Result Type 2.16.840.1.113883.3.88.12.80.62 DYNAMIC (CONF:7301).

        Knowing what kind of observation is being made is essential to understanding the observation.

        Alternate NamesName, Test
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        20. Observation.code.coding
        Definition

        A reference to a code defined by a terminology system.

        ShortCode defined by a terminology system
        Comments

        Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

        Control10..*
        TypeCoding
        Is Modifierfalse
        Summarytrue
        Requirements

        Allows for alternative encodings within a code system, and translations to other code systems.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        SlicingThis element introduces a set of slices on Observation.code.coding. The slices areUnordered and Open, and can be differentiated using the following discriminators:
        • value @ code
        • value @ system
        • 22. Observation.code.coding:BodyWeightCode
          Slice NameBodyWeightCode
          Definition

          A reference to a code defined by a terminology system.

          ShortCode defined by a terminology system
          Comments

          Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

          Control10..1*
          TypeCoding
          Is Modifierfalse
          Summarytrue
          Requirements

          Allows for alternative encodings within a code system, and translations to other code systems.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          24. Observation.code.coding:BodyWeightCode.system
          Definition

          The identification of the code system that defines the meaning of the symbol in the code.

          ShortIdentity of the terminology system
          Comments

          The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

          Control10..1
          Typeuri
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Summarytrue
          Requirements

          Need to be unambiguous about the source of the definition of the symbol.

          Fixed Valuehttp://loinc.org
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          26. Observation.code.coding:BodyWeightCode.code
          Definition

          A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

          ShortSymbol in syntax defined by the system
          Control10..1
          Typecode
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Summarytrue
          Requirements

          Need to refer to a particular code in the system.

          Fixed Value29463-7
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          28. Observation.subject
          Definition

          The patient, or group of patients, location, or device this observation is about and into whose record the observation is placed. If the actual focus of the observation is different from the subject (or a sample of, part, or region of the subject), the focus element or the code itself specifies the actual focus of the observation.

          ShortWho and/or what the observation is about
          Comments

          One would expect this element to be a cardinality of 1..1. The only circumstance in which the subject can be missing is when the observation is made by a device that does not know the patient. In this case, the observation SHALL be matched to a patient through some context/channel matching technique, and at this point, the observation should be updated.

          Control10..1
          TypeReference(Patient, Group, Device, Location)
          Is Modifierfalse
          Must Supporttrue
          Summarytrue
          Requirements

          Observations have no value if you don't know who or what they're about.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          30. Observation.effective[x]
          Definition

          Often just a dateTime for Vital Signs.


          The time or time-period the observed value is asserted as being true. For biological subjects - e.g. human patients - this is usually called the "physiologically relevant time". This is usually either the time of the procedure or of specimen collection, but very often the source of the date/time is not known, only the date/time itself.

          ShortOften just a dateTime for Vital SignsClinically relevant time/time-period for observation
          Comments

          At least a date should be present unless this observation is a historical report. For recording imprecise or "fuzzy" times (For example, a blood glucose measurement taken "after breakfast") use the Timing datatype which allow the measurement to be tied to regular life events.


          At least a date should be present unless this observation is a historical report. For recording imprecise or "fuzzy" times (For example, a blood glucose measurement taken "after breakfast") use the Timing datatype which allow the measurement to be tied to regular life events.

          Control10..1
          This element is affected by the following invariants: vs-1
          TypeChoice of: dateTime, Period, Timing, instant
          [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Must Supporttrue
          Must Support TypesNo must-support rules about the choice of types/profiles
          Summarytrue
          Requirements

          Knowing when an observation was deemed true is important to its relevance as well as determining trends.

          Alternate NamesOccurrence
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          vs-1: if Observation.effective[x] is dateTime and has a value then that value shall be precise to the day ($this is dateTime implies $this.toString().length() >= 10)
          32. Observation.value[x]
          Definition

          Vital Signs value are recorded using the Quantity data type. For supporting observations such as Cuff size could use other datatypes such as CodeableConcept.


          The information determined as a result of making the observation, if the information has a simple value.

          ShortVital Signs value are recorded using the Quantity data type. For supporting observations such as Cuff size could use other datatypes such as CodeableConcept.Actual result
          Comments

          An observation may have; 1) a single value here, 2) both a value and a set of related or component values, or 3) only a set of related or component values. If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.


          An observation may have; 1) a single value here, 2) both a value and a set of related or component values, or 3) only a set of related or component values. If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

          Control0..1
          This element is affected by the following invariants: obs-7, vs-2
          TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
          [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Must Supporttrue
          Must Support TypesNo must-support rules about the choice of types/profiles
          Summarytrue
          Requirements
          1. SHALL contain exactly one [1..1] value with @xsi:type="PQ" (CONF:7305).

          An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          SlicingThis element introduces a set of slices on Observation.value[x]. The slices areUnordered and Open, and can be differentiated using the following discriminators:
          • type @ $this
          • 34. Observation.value[x]:valueQuantity
            Slice NamevalueQuantity
            Definition

            Vital Signs value are recorded using the Quantity data type. For supporting observations such as Cuff size could use other datatypes such as CodeableConcept.


            The information determined as a result of making the observation, if the information has a simple value.

            ShortVital Signs value are recorded using the Quantity data type. For supporting observations such as Cuff size could use other datatypes such as CodeableConcept.Actual result
            Comments

            An observation may have; 1) a single value here, 2) both a value and a set of related or component values, or 3) only a set of related or component values. If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.


            An observation may have; 1) a single value here, 2) both a value and a set of related or component values, or 3) only a set of related or component values. If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

            Control0..1
            This element is affected by the following invariants: obs-7, vs-2
            TypeQuantity, dateTime, boolean, string, SampledData, Period, Ratio, integer, time, Range, CodeableConcept
            [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
            Is Modifierfalse
            Must Supporttrue
            Summarytrue
            Requirements
            1. SHALL contain exactly one [1..1] value with @xsi:type="PQ" (CONF:7305).

            An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            36. Observation.value[x]:valueQuantity.value
            Definition

            The value of the measured amount. The value includes an implicit precision in the presentation of the value.

            ShortNumerical value (with implicit precision)
            Comments

            The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

            Control10..1
            Typedecimal
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Summarytrue
            Requirements

            Precision is handled implicitly in almost all cases of measurement.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            38. Observation.value[x]:valueQuantity.comparator
            Definition

            How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

            Short< | <= | >= | > - how to understand the value
            Control0..1
            BindingThe codes SHALL be taken from QuantityComparatorhttp://hl7.org/fhir/ValueSet/quantity-comparator|4.0.1
            (required to http://hl7.org/fhir/ValueSet/quantity-comparator|4.0.1)

            How the Quantity should be understood and represented.

            Typecode
            Is Modifiertrue because This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Summarytrue
            Requirements

            Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

            Meaning if MissingIf there is no comparator, then there is no modification of the value
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            40. Observation.value[x]:valueQuantity.unit
            Definition

            A human-readable form of the unit.

            ShortUnit representation
            Control10..1
            Typestring
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Summarytrue
            Requirements

            There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            42. Observation.value[x]:valueQuantity.system
            Definition

            The identification of the system that provides the coded form of the unit.

            ShortSystem that defines coded unit form
            Control10..1
            This element is affected by the following invariants: qty-3
            Typeuri
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Summarytrue
            Requirements

            Need to know the system that defines the coded form of the unit.

            Fixed Valuehttp://unitsofmeasure.org
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            44. Observation.value[x]:valueQuantity.code
            Definition

            Coded responses from the common UCUM units for vital signs value set.


            A computer processable form of the unit in some unit representation system.

            ShortCoded responses from the common UCUM units for vital signs value set.Coded form of the unit
            Comments

            The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency. The context of use may additionally require a code from a particular system.

            Control10..1
            BindingThe codes SHALL be taken from For codes, see BodyWeightUnits
            (required to http://hl7.org/fhir/ValueSet/ucum-bodyweight|4.0.1)

            Common UCUM units for Body Weight.

            Typecode
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Summarytrue
            Requirements

            Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            46. Observation.dataAbsentReason
            Definition

            Provides a reason why the expected value in the element Observation.value[x] is missing.

            ShortWhy the result is missing
            Comments

            Null or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "specimen unsatisfactory".

            The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Note that an observation may only be reported if there are values to report. For example differential cell counts values may be reported only when > 0. Because of these options, use-case agreements are required to interpret general observations for null or exceptional values.

            Control0..1
            This element is affected by the following invariants: obs-6, vs-2
            BindingUnless not suitable, these codes SHALL be taken from DataAbsentReasonhttp://hl7.org/fhir/ValueSet/data-absent-reason
            (extensible to http://hl7.org/fhir/ValueSet/data-absent-reason)

            Codes specifying why the result (Observation.value[x]) is missing.

            TypeCodeableConcept
            Is Modifierfalse
            Must Supporttrue
            Summaryfalse
            Requirements

            For many results it is necessary to handle exceptional values in measurements.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            48. Observation.component
            Definition

            Used when reporting systolic and diastolic blood pressure.


            Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

            ShortUsed when reporting systolic and diastolic blood pressure.Component results
            Comments

            For a discussion on the ways Observations can be assembled in groups together see Notes below.


            For a discussion on the ways Observations can be assembled in groups together see Notes below.

            Control0..*
            TypeBackboneElement
            Is Modifierfalse
            Must Supporttrue
            Summarytrue
            Requirements

            Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            vs-3: If there is no a value a data absent reason must be present (value.exists() or dataAbsentReason.exists())
            50. Observation.component.modifierExtension
            Definition

            May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

            Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

            ShortExtensions that cannot be ignored even if unrecognized
            Comments

            There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

            Control0..*
            TypeExtension
            Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
            Summarytrue
            Requirements

            Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.


            Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

            Alternate Namesextensions, user content, modifiers
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
            52. Observation.component.code
            Definition

            Describes what was observed. Sometimes this is called the observation "code".

            ShortType of component observation (code / type)
            Comments

            All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

            Control1..1
            BindingUnless not suitable, these codes SHALL be taken from For example codes, see VitalSignshttp://hl7.org/fhir/ValueSet/observation-codes
            (extensible to http://hl7.org/fhir/ValueSet/observation-vitalsignresult)

            This identifies the vital sign result type.


            Codes identifying names of simple observations.

            TypeCodeableConcept
            Is Modifierfalse
            Must Supporttrue
            Summarytrue
            Requirements

            Knowing what kind of observation is being made is essential to understanding the observation.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            54. Observation.component.value[x]
            Definition

            Vital Sign Value recorded with UCUM.


            The information determined as a result of making the observation, if the information has a simple value.

            ShortVital Sign Value recorded with UCUMActual component result
            Comments

            Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.


            Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

            Control0..1
            This element is affected by the following invariants: vs-3
            BindingUnless not suitable, these codes SHALL be taken from For codes, see VitalSignsUnits
            (extensible to http://hl7.org/fhir/ValueSet/ucum-vitals-common|4.0.1)

            Common UCUM units for recording Vital Signs.

            TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
            [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Must Support TypesNo must-support rules about the choice of types/profiles
            Summarytrue
            Requirements
            1. SHALL contain exactly one [1..1] value with @xsi:type="PQ" (CONF:7305).

            An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            56. Observation.component.dataAbsentReason
            Definition

            Provides a reason why the expected value in the element Observation.component.value[x] is missing.

            ShortWhy the component result is missing
            Comments

            "Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

            The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

            Control0..1
            This element is affected by the following invariants: obs-6, vs-3
            BindingUnless not suitable, these codes SHALL be taken from DataAbsentReasonhttp://hl7.org/fhir/ValueSet/data-absent-reason
            (extensible to http://hl7.org/fhir/ValueSet/data-absent-reason)

            Codes specifying why the result (Observation.value[x]) is missing.

            TypeCodeableConcept
            Is Modifierfalse
            Must Supporttrue
            Summaryfalse
            Requirements

            For many results it is necessary to handle exceptional values in measurements.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))

            Guidance on how to interpret the contents of this table can be found here

            0. Observation
            Definition

            This profile defines how to represent body weight observations in FHIR using a standard LOINC code and UCUM units of measure.

            ShortFHIR Body Weight Profile
            Comments

            Used for simple observations such as device measurements, laboratory atomic results, vital signs, height, weight, smoking status, comments, etc. Other resources are used to provide context for observations such as laboratory reports, etc.

            Control0..*
            Is Modifierfalse
            Summaryfalse
            Alternate NamesVital Signs, Measurement, Results, Tests
            Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
            dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
            dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
            dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
            dom-6: A resource should have narrative for robust management (text.`div`.exists())
            obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present (dataAbsentReason.empty() or value.empty())
            obs-7: If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present (value.empty() or component.code.where(coding.intersect(%resource.code.coding).exists()).empty())
            vs-2: If there is no component or hasMember element then either a value[x] or a data absent reason must be present. ((component.empty() and hasMember.empty()) implies (dataAbsentReason.exists() or value.exists()))
            2. Observation.id
            Definition

            The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

            ShortLogical id of this artifact
            Comments

            The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

            Control0..1
            Typeid
            Is Modifierfalse
            Summarytrue
            4. Observation.meta
            Definition

            The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

            ShortMetadata about the resource
            Control0..1
            TypeMeta
            Is Modifierfalse
            Summarytrue
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            6. Observation.implicitRules
            Definition

            A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

            ShortA set of rules under which this content was created
            Comments

            Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

            Control0..1
            Typeuri
            Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Summarytrue
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            8. Observation.language
            Definition

            The base language in which the resource is written.

            ShortLanguage of the resource content
            Comments

            Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

            Control0..1
            BindingThe codes SHOULD be taken from CommonLanguages
            (preferred to http://hl7.org/fhir/ValueSet/languages)

            A human language.

            Additional BindingsPurpose
            AllLanguagesMax Binding
            Typecode
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Summaryfalse
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            10. Observation.text
            Definition

            A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

            ShortText summary of the resource, for human interpretation
            Comments

            Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

            Control0..1
            TypeNarrative
            Is Modifierfalse
            Summaryfalse
            Alternate Namesnarrative, html, xhtml, display
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            12. Observation.contained
            Definition

            These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

            ShortContained, inline Resources
            Comments

            This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

            Control0..*
            TypeResource
            Is Modifierfalse
            Summaryfalse
            Alternate Namesinline resources, anonymous resources, contained resources
            14. Observation.extension
            Definition

            May be used to represent additional information that is not part of the basic definition of the resource. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

            ShortAdditional content defined by implementations
            Comments

            There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

            Control0..*
            TypeExtension
            Is Modifierfalse
            Summaryfalse
            Alternate Namesextensions, user content
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
            16. Observation.modifierExtension
            Definition

            May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

            Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

            ShortExtensions that cannot be ignored
            Comments

            There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

            Control0..*
            TypeExtension
            Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
            Summaryfalse
            Requirements

            Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

            Alternate Namesextensions, user content
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
            18. Observation.identifier
            Definition

            A unique identifier assigned to this observation.

            ShortBusiness Identifier for observation
            NoteThis is a business identifier, not a resource identifier (see discussion)
            Control0..*
            TypeIdentifier
            Is Modifierfalse
            Summarytrue
            Requirements

            Allows observations to be distinguished and referenced.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            20. Observation.basedOn
            Definition

            A plan, proposal or order that is fulfilled in whole or in part by this event. For example, a MedicationRequest may require a patient to have laboratory test performed before it is dispensed.

            ShortFulfills plan, proposal or order
            Control0..*
            TypeReference(CarePlan, DeviceRequest, ImmunizationRecommendation, MedicationRequest, NutritionOrder, ServiceRequest)
            Is Modifierfalse
            Summarytrue
            Requirements

            Allows tracing of authorization for the event and tracking whether proposals/recommendations were acted upon.

            Alternate NamesFulfills
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            22. Observation.partOf
            Definition

            A larger event of which this particular Observation is a component or step. For example, an observation as part of a procedure.

            ShortPart of referenced event
            Comments

            To link an Observation to an Encounter use encounter. See the Notes below for guidance on referencing another Observation.

            Control0..*
            TypeReference(MedicationAdministration, MedicationDispense, MedicationStatement, Procedure, Immunization, ImagingStudy)
            Is Modifierfalse
            Summarytrue
            Alternate NamesContainer
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            24. Observation.status
            Definition

            The status of the result value.

            Shortregistered | preliminary | final | amended +
            Comments

            This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

            Control1..1
            BindingThe codes SHALL be taken from ObservationStatus
            (required to http://hl7.org/fhir/ValueSet/observation-status|4.0.1)
            Typecode
            Is Modifiertrue because This element is labeled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Summarytrue
            Requirements

            Need to track the status of individual results. Some results are finalized before the whole report is finalized.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            26. Observation.category
            Definition

            A code that classifies the general type of observation being made.

            ShortClassification of type of observation
            Comments

            In addition to the required category valueset, this element allows various categorization schemes based on the owner’s definition of the category and effectively multiple categories can be used at once. The level of granularity is defined by the category concepts in the value set.

            Control1..*
            BindingThe codes SHOULD be taken from ObservationCategoryCodes
            (preferred to http://hl7.org/fhir/ValueSet/observation-category)

            Codes for high level observation categories.

            TypeCodeableConcept
            Is Modifierfalse
            Must Supporttrue
            Summaryfalse
            Requirements

            Used for filtering what observations are retrieved and displayed.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            SlicingThis element introduces a set of slices on Observation.category. The slices areUnordered and Open, and can be differentiated using the following discriminators:
            • value @ coding.code
            • value @ coding.system
            • 28. Observation.category:VSCat
              Slice NameVSCat
              Definition

              A code that classifies the general type of observation being made.

              ShortClassification of type of observation
              Comments

              In addition to the required category valueset, this element allows various categorization schemes based on the owner’s definition of the category and effectively multiple categories can be used at once. The level of granularity is defined by the category concepts in the value set.

              Control1..1
              BindingThe codes SHOULD be taken from ObservationCategoryCodes
              (preferred to http://hl7.org/fhir/ValueSet/observation-category)

              Codes for high level observation categories.

              TypeCodeableConcept
              Is Modifierfalse
              Must Supporttrue
              Summaryfalse
              Requirements

              Used for filtering what observations are retrieved and displayed.

              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
              30. Observation.category:VSCat.id
              Definition

              Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

              ShortUnique id for inter-element referencing
              Control0..1
              Typestring
              Is Modifierfalse
              XML FormatIn the XML format, this property is represented as an attribute.
              Summaryfalse
              32. Observation.category:VSCat.extension
              Definition

              May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

              ShortAdditional content defined by implementations
              Comments

              There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

              Control0..*
              TypeExtension
              Is Modifierfalse
              Summaryfalse
              Alternate Namesextensions, user content
              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
              ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
              SlicingThis element introduces a set of slices on Observation.category.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
              • value @ url
              • 34. Observation.category:VSCat.coding
                Definition

                A reference to a code defined by a terminology system.

                ShortCode defined by a terminology system
                Comments

                Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

                Control1..*
                TypeCoding
                Is Modifierfalse
                Must Supporttrue
                Summarytrue
                Requirements

                Allows for alternative encodings within a code system, and translations to other code systems.

                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                36. Observation.category:VSCat.coding.id
                Definition

                Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                ShortUnique id for inter-element referencing
                Control0..1
                Typestring
                Is Modifierfalse
                XML FormatIn the XML format, this property is represented as an attribute.
                Summaryfalse
                38. Observation.category:VSCat.coding.extension
                Definition

                May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                ShortAdditional content defined by implementations
                Comments

                There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                Control0..*
                TypeExtension
                Is Modifierfalse
                Summaryfalse
                Alternate Namesextensions, user content
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                SlicingThis element introduces a set of slices on Observation.category.coding.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                • value @ url
                • 40. Observation.category:VSCat.coding.system
                  Definition

                  The identification of the code system that defines the meaning of the symbol in the code.

                  ShortIdentity of the terminology system
                  Comments

                  The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

                  Control1..1
                  Typeuri
                  Is Modifierfalse
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Must Supporttrue
                  Summarytrue
                  Requirements

                  Need to be unambiguous about the source of the definition of the symbol.

                  Fixed Valuehttp://terminology.hl7.org/CodeSystem/observation-category
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  42. Observation.category:VSCat.coding.version
                  Definition

                  The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

                  ShortVersion of the system - if relevant
                  Comments

                  Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

                  NoteThis is a business version Id, not a resource version Id (see discussion)
                  Control0..1
                  Typestring
                  Is Modifierfalse
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Summarytrue
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  44. Observation.category:VSCat.coding.code
                  Definition

                  A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

                  ShortSymbol in syntax defined by the system
                  Control1..1
                  Typecode
                  Is Modifierfalse
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Must Supporttrue
                  Summarytrue
                  Requirements

                  Need to refer to a particular code in the system.

                  Fixed Valuevital-signs
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  46. Observation.category:VSCat.coding.display
                  Definition

                  A representation of the meaning of the code in the system, following the rules of the system.

                  ShortRepresentation defined by the system
                  Control0..1
                  Typestring
                  Is Modifierfalse
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Summarytrue
                  Requirements

                  Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  48. Observation.category:VSCat.coding.userSelected
                  Definition

                  Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

                  ShortIf this coding was chosen directly by the user
                  Comments

                  Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

                  Control0..1
                  Typeboolean
                  Is Modifierfalse
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Summarytrue
                  Requirements

                  This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  50. Observation.category:VSCat.text
                  Definition

                  A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

                  ShortPlain text representation of the concept
                  Comments

                  Very often the text is the same as a displayName of one of the codings.

                  Control0..1
                  Typestring
                  Is Modifierfalse
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Summarytrue
                  Requirements

                  The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  52. Observation.code
                  Definition

                  Body Weight.

                  ShortBody Weight
                  Comments

                  additional codes that translate or map to this code are allowed. For example a more granular LOINC code or code that is used locally in a system.

                  Control1..1
                  BindingUnless not suitable, these codes SHALL be taken from VitalSigns
                  (extensible to http://hl7.org/fhir/ValueSet/observation-vitalsignresult)

                  This identifies the vital sign result type.

                  TypeCodeableConcept
                  Is Modifierfalse
                  Must Supporttrue
                  Summarytrue
                  Requirements
                  1. SHALL contain exactly one [1..1] code, where the @code SHOULD be selected from ValueSet HITSP Vital Sign Result Type 2.16.840.1.113883.3.88.12.80.62 DYNAMIC (CONF:7301).
                  Alternate NamesName, Test
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  54. Observation.code.id
                  Definition

                  Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                  ShortUnique id for inter-element referencing
                  Control0..1
                  Typestring
                  Is Modifierfalse
                  XML FormatIn the XML format, this property is represented as an attribute.
                  Summaryfalse
                  56. Observation.code.extension
                  Definition

                  May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                  ShortAdditional content defined by implementations
                  Comments

                  There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                  Control0..*
                  TypeExtension
                  Is Modifierfalse
                  Summaryfalse
                  Alternate Namesextensions, user content
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                  SlicingThis element introduces a set of slices on Observation.code.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                  • value @ url
                  • 58. Observation.code.coding
                    Definition

                    A reference to a code defined by a terminology system.

                    ShortCode defined by a terminology system
                    Comments

                    Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

                    Control1..*
                    TypeCoding
                    Is Modifierfalse
                    Summarytrue
                    Requirements

                    Allows for alternative encodings within a code system, and translations to other code systems.

                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    SlicingThis element introduces a set of slices on Observation.code.coding. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                    • value @ code
                    • value @ system
                    • 60. Observation.code.coding:BodyWeightCode
                      Slice NameBodyWeightCode
                      Definition

                      A reference to a code defined by a terminology system.

                      ShortCode defined by a terminology system
                      Comments

                      Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

                      Control1..1
                      TypeCoding
                      Is Modifierfalse
                      Summarytrue
                      Requirements

                      Allows for alternative encodings within a code system, and translations to other code systems.

                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                      62. Observation.code.coding:BodyWeightCode.id
                      Definition

                      Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                      ShortUnique id for inter-element referencing
                      Control0..1
                      Typestring
                      Is Modifierfalse
                      XML FormatIn the XML format, this property is represented as an attribute.
                      Summaryfalse
                      64. Observation.code.coding:BodyWeightCode.extension
                      Definition

                      May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                      ShortAdditional content defined by implementations
                      Comments

                      There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                      Control0..*
                      TypeExtension
                      Is Modifierfalse
                      Summaryfalse
                      Alternate Namesextensions, user content
                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                      SlicingThis element introduces a set of slices on Observation.code.coding.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                      • value @ url
                      • 66. Observation.code.coding:BodyWeightCode.system
                        Definition

                        The identification of the code system that defines the meaning of the symbol in the code.

                        ShortIdentity of the terminology system
                        Comments

                        The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

                        Control1..1
                        Typeuri
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Summarytrue
                        Requirements

                        Need to be unambiguous about the source of the definition of the symbol.

                        Fixed Valuehttp://loinc.org
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        68. Observation.code.coding:BodyWeightCode.version
                        Definition

                        The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

                        ShortVersion of the system - if relevant
                        Comments

                        Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

                        NoteThis is a business version Id, not a resource version Id (see discussion)
                        Control0..1
                        Typestring
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Summarytrue
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        70. Observation.code.coding:BodyWeightCode.code
                        Definition

                        A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

                        ShortSymbol in syntax defined by the system
                        Control1..1
                        Typecode
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Summarytrue
                        Requirements

                        Need to refer to a particular code in the system.

                        Fixed Value29463-7
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        72. Observation.code.coding:BodyWeightCode.display
                        Definition

                        A representation of the meaning of the code in the system, following the rules of the system.

                        ShortRepresentation defined by the system
                        Control0..1
                        Typestring
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Summarytrue
                        Requirements

                        Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        74. Observation.code.coding:BodyWeightCode.userSelected
                        Definition

                        Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

                        ShortIf this coding was chosen directly by the user
                        Comments

                        Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

                        Control0..1
                        Typeboolean
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Summarytrue
                        Requirements

                        This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        76. Observation.code.text
                        Definition

                        A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

                        ShortPlain text representation of the concept
                        Comments

                        Very often the text is the same as a displayName of one of the codings.

                        Control0..1
                        Typestring
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Summarytrue
                        Requirements

                        The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        78. Observation.subject
                        Definition

                        The patient, or group of patients, location, or device this observation is about and into whose record the observation is placed. If the actual focus of the observation is different from the subject (or a sample of, part, or region of the subject), the focus element or the code itself specifies the actual focus of the observation.

                        ShortWho and/or what the observation is about
                        Comments

                        One would expect this element to be a cardinality of 1..1. The only circumstance in which the subject can be missing is when the observation is made by a device that does not know the patient. In this case, the observation SHALL be matched to a patient through some context/channel matching technique, and at this point, the observation should be updated.

                        Control1..1
                        TypeReference(Patient)
                        Is Modifierfalse
                        Must Supporttrue
                        Summarytrue
                        Requirements

                        Observations have no value if you don't know who or what they're about.

                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        80. Observation.focus
                        Definition

                        The actual focus of an observation when it is not the patient of record representing something or someone associated with the patient such as a spouse, parent, fetus, or donor. For example, fetus observations in a mother's record. The focus of an observation could also be an existing condition, an intervention, the subject's diet, another observation of the subject, or a body structure such as tumor or implanted device. An example use case would be using the Observation resource to capture whether the mother is trained to change her child's tracheostomy tube. In this example, the child is the patient of record and the mother is the focus.

                        ShortWhat the observation is about, when it is not about the subject of record
                        Comments

                        Typically, an observation is made about the subject - a patient, or group of patients, location, or device - and the distinction between the subject and what is directly measured for an observation is specified in the observation code itself ( e.g., "Blood Glucose") and does not need to be represented separately using this element. Use specimen if a reference to a specimen is required. If a code is required instead of a resource use either bodysite for bodysites or the standard extension focusCode.

                        Control0..*
                        TypeReference(Resource)
                        Is Modifierfalse
                        Summarytrue
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        82. Observation.encounter
                        Definition

                        The healthcare event (e.g. a patient and healthcare provider interaction) during which this observation is made.

                        ShortHealthcare event during which this observation is made
                        Comments

                        This will typically be the encounter the event occurred within, but some events may be initiated prior to or after the official completion of an encounter but still be tied to the context of the encounter (e.g. pre-admission laboratory tests).

                        Control0..1
                        TypeReference(Encounter)
                        Is Modifierfalse
                        Summarytrue
                        Requirements

                        For some observations it may be important to know the link between an observation and a particular encounter.

                        Alternate NamesContext
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        84. Observation.effective[x]
                        Definition

                        Often just a dateTime for Vital Signs.

                        ShortOften just a dateTime for Vital Signs
                        Comments

                        At least a date should be present unless this observation is a historical report. For recording imprecise or "fuzzy" times (For example, a blood glucose measurement taken "after breakfast") use the Timing datatype which allow the measurement to be tied to regular life events.

                        Control1..1
                        This element is affected by the following invariants: vs-1
                        TypeChoice of: dateTime, Period
                        [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Must Supporttrue
                        Must Support TypesNo must-support rules about the choice of types/profiles
                        Summarytrue
                        Requirements

                        Knowing when an observation was deemed true is important to its relevance as well as determining trends.

                        Alternate NamesOccurrence
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        vs-1: if Observation.effective[x] is dateTime and has a value then that value shall be precise to the day ($this is dateTime implies $this.toString().length() >= 10)
                        86. Observation.issued
                        Definition

                        The date and time this version of the observation was made available to providers, typically after the results have been reviewed and verified.

                        ShortDate/Time this version was made available
                        Comments

                        For Observations that don’t require review and verification, it may be the same as the lastUpdated time of the resource itself. For Observations that do require review and verification for certain updates, it might not be the same as the lastUpdated time of the resource itself due to a non-clinically significant update that doesn’t require the new version to be reviewed and verified again.

                        Control0..1
                        Typeinstant
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Summarytrue
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        88. Observation.performer
                        Definition

                        Who was responsible for asserting the observed value as "true".

                        ShortWho is responsible for the observation
                        Control0..*
                        TypeReference(Practitioner, PractitionerRole, Organization, CareTeam, Patient, RelatedPerson)
                        Is Modifierfalse
                        Summarytrue
                        Requirements

                        May give a degree of confidence in the observation and also indicates where follow-up questions should be directed.

                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        90. Observation.value[x]
                        Definition

                        Vital Signs value are recorded using the Quantity data type. For supporting observations such as Cuff size could use other datatypes such as CodeableConcept.

                        ShortVital Signs value are recorded using the Quantity data type. For supporting observations such as Cuff size could use other datatypes such as CodeableConcept.
                        Comments

                        An observation may have; 1) a single value here, 2) both a value and a set of related or component values, or 3) only a set of related or component values. If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

                        Control0..1
                        This element is affected by the following invariants: obs-7, vs-2
                        TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
                        [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                        Is Modifierfalse
                        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                        Must Supporttrue
                        Must Support TypesNo must-support rules about the choice of types/profiles
                        Summarytrue
                        Requirements
                        1. SHALL contain exactly one [1..1] value with @xsi:type="PQ" (CONF:7305).
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        SlicingThis element introduces a set of slices on Observation.value[x]. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                        • type @ $this
                        • 92. Observation.value[x]:valueQuantity
                          Slice NamevalueQuantity
                          Definition

                          Vital Signs value are recorded using the Quantity data type. For supporting observations such as Cuff size could use other datatypes such as CodeableConcept.

                          ShortVital Signs value are recorded using the Quantity data type. For supporting observations such as Cuff size could use other datatypes such as CodeableConcept.
                          Comments

                          An observation may have; 1) a single value here, 2) both a value and a set of related or component values, or 3) only a set of related or component values. If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

                          Control0..1
                          This element is affected by the following invariants: obs-7, vs-2
                          TypeQuantity
                          [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                          Is Modifierfalse
                          Must Supporttrue
                          Summarytrue
                          Requirements
                          1. SHALL contain exactly one [1..1] value with @xsi:type="PQ" (CONF:7305).
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          94. Observation.value[x]:valueQuantity.id
                          Definition

                          Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                          ShortUnique id for inter-element referencing
                          Control0..1
                          Typestring
                          Is Modifierfalse
                          XML FormatIn the XML format, this property is represented as an attribute.
                          Summaryfalse
                          96. Observation.value[x]:valueQuantity.extension
                          Definition

                          May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                          ShortAdditional content defined by implementations
                          Comments

                          There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                          Control0..*
                          TypeExtension
                          Is Modifierfalse
                          Summaryfalse
                          Alternate Namesextensions, user content
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                          SlicingThis element introduces a set of slices on Observation.value[x].extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                          • value @ url
                          • 98. Observation.value[x]:valueQuantity.value
                            Definition

                            The value of the measured amount. The value includes an implicit precision in the presentation of the value.

                            ShortNumerical value (with implicit precision)
                            Comments

                            The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

                            Control1..1
                            Typedecimal
                            Is Modifierfalse
                            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                            Must Supporttrue
                            Summarytrue
                            Requirements

                            Precision is handled implicitly in almost all cases of measurement.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            100. Observation.value[x]:valueQuantity.comparator
                            Definition

                            How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

                            Short< | <= | >= | > - how to understand the value
                            Control0..1
                            BindingThe codes SHALL be taken from QuantityComparator
                            (required to http://hl7.org/fhir/ValueSet/quantity-comparator|4.0.1)

                            How the Quantity should be understood and represented.

                            Typecode
                            Is Modifiertrue because This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value
                            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                            Summarytrue
                            Requirements

                            Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

                            Meaning if MissingIf there is no comparator, then there is no modification of the value
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            102. Observation.value[x]:valueQuantity.unit
                            Definition

                            A human-readable form of the unit.

                            ShortUnit representation
                            Control1..1
                            Typestring
                            Is Modifierfalse
                            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                            Must Supporttrue
                            Summarytrue
                            Requirements

                            There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            104. Observation.value[x]:valueQuantity.system
                            Definition

                            The identification of the system that provides the coded form of the unit.

                            ShortSystem that defines coded unit form
                            Control1..1
                            This element is affected by the following invariants: qty-3
                            Typeuri
                            Is Modifierfalse
                            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                            Must Supporttrue
                            Summarytrue
                            Requirements

                            Need to know the system that defines the coded form of the unit.

                            Fixed Valuehttp://unitsofmeasure.org
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            106. Observation.value[x]:valueQuantity.code
                            Definition

                            Coded responses from the common UCUM units for vital signs value set.

                            ShortCoded responses from the common UCUM units for vital signs value set.
                            Comments

                            The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency. The context of use may additionally require a code from a particular system.

                            Control1..1
                            BindingThe codes SHALL be taken from BodyWeightUnits
                            (required to http://hl7.org/fhir/ValueSet/ucum-bodyweight|4.0.1)

                            Common UCUM units for Body Weight.

                            Typecode
                            Is Modifierfalse
                            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                            Must Supporttrue
                            Summarytrue
                            Requirements

                            Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            108. Observation.dataAbsentReason
                            Definition

                            Provides a reason why the expected value in the element Observation.value[x] is missing.

                            ShortWhy the result is missing
                            Comments

                            Null or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "specimen unsatisfactory".

                            The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Note that an observation may only be reported if there are values to report. For example differential cell counts values may be reported only when > 0. Because of these options, use-case agreements are required to interpret general observations for null or exceptional values.

                            Control0..1
                            This element is affected by the following invariants: obs-6, vs-2
                            BindingUnless not suitable, these codes SHALL be taken from DataAbsentReason
                            (extensible to http://hl7.org/fhir/ValueSet/data-absent-reason)

                            Codes specifying why the result (Observation.value[x]) is missing.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Must Supporttrue
                            Summaryfalse
                            Requirements

                            For many results it is necessary to handle exceptional values in measurements.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            110. Observation.interpretation
                            Definition

                            A categorical assessment of an observation value. For example, high, low, normal.

                            ShortHigh, low, normal, etc.
                            Comments

                            Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

                            Control0..*
                            BindingUnless not suitable, these codes SHALL be taken from ObservationInterpretationCodes
                            (extensible to http://hl7.org/fhir/ValueSet/observation-interpretation)

                            Codes identifying interpretations of observations.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

                            Alternate NamesAbnormal Flag
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            112. Observation.note
                            Definition

                            Comments about the observation or the results.

                            ShortComments about the observation
                            Comments

                            May include general statements about the observation, or statements about significant, unexpected or unreliable results values, or information about its source when relevant to its interpretation.

                            Control0..*
                            TypeAnnotation
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            Need to be able to provide free text additional information.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            114. Observation.bodySite
                            Definition

                            Indicates the site on the subject's body where the observation was made (i.e. the target site).

                            ShortObserved body part
                            Comments

                            Only used if not implicit in code found in Observation.code. In many systems, this may be represented as a related observation instead of an inline component.

                            If the use case requires BodySite to be handled as a separate resource (e.g. to identify and track separately) then use the standard extension bodySite.

                            Control0..1
                            BindingFor example codes, see SNOMEDCTBodyStructures
                            (example to http://hl7.org/fhir/ValueSet/body-site)

                            Codes describing anatomical locations. May include laterality.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Summaryfalse
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            116. Observation.method
                            Definition

                            Indicates the mechanism used to perform the observation.

                            ShortHow it was done
                            Comments

                            Only used if not implicit in code for Observation.code.

                            Control0..1
                            BindingFor example codes, see ObservationMethods
                            (example to http://hl7.org/fhir/ValueSet/observation-methods)

                            Methods for simple observations.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            In some cases, method can impact results and is thus used for determining whether results can be compared or determining significance of results.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            118. Observation.specimen
                            Definition

                            The specimen that was used when this observation was made.

                            ShortSpecimen used for this observation
                            Comments

                            Should only be used if not implicit in code found in Observation.code. Observations are not made on specimens themselves; they are made on a subject, but in many cases by the means of a specimen. Note that although specimens are often involved, they are not always tracked and reported explicitly. Also note that observation resources may be used in contexts that track the specimen explicitly (e.g. Diagnostic Report).

                            Control0..1
                            TypeReference(Specimen)
                            Is Modifierfalse
                            Summaryfalse
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            120. Observation.device
                            Definition

                            The device used to generate the observation data.

                            Short(Measurement) Device
                            Comments

                            Note that this is not meant to represent a device involved in the transmission of the result, e.g., a gateway. Such devices may be documented using the Provenance resource where relevant.

                            Control0..1
                            TypeReference(Device, DeviceMetric)
                            Is Modifierfalse
                            Summaryfalse
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            122. Observation.referenceRange
                            Definition

                            Guidance on how to interpret the value by comparison to a normal or recommended range. Multiple reference ranges are interpreted as an "OR". In other words, to represent two distinct target populations, two referenceRange elements would be used.

                            ShortProvides guide for interpretation
                            Comments

                            Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

                            Control0..*
                            TypeBackboneElement
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            obs-3: Must have at least a low or a high or text (low.exists() or high.exists() or text.exists())
                            124. Observation.referenceRange.id
                            Definition

                            Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                            ShortUnique id for inter-element referencing
                            Control0..1
                            Typestring
                            Is Modifierfalse
                            XML FormatIn the XML format, this property is represented as an attribute.
                            Summaryfalse
                            126. Observation.referenceRange.extension
                            Definition

                            May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                            ShortAdditional content defined by implementations
                            Comments

                            There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                            Control0..*
                            TypeExtension
                            Is Modifierfalse
                            Summaryfalse
                            Alternate Namesextensions, user content
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                            128. Observation.referenceRange.modifierExtension
                            Definition

                            May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

                            Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

                            ShortExtensions that cannot be ignored even if unrecognized
                            Comments

                            There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                            Control0..*
                            TypeExtension
                            Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
                            Summarytrue
                            Requirements

                            Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

                            Alternate Namesextensions, user content, modifiers
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                            130. Observation.referenceRange.low
                            Definition

                            The value of the low bound of the reference range. The low bound of the reference range endpoint is inclusive of the value (e.g. reference range is >=5 - <=9). If the low bound is omitted, it is assumed to be meaningless (e.g. reference range is <=2.3).

                            ShortLow Range, if relevant
                            Control0..1
                            This element is affected by the following invariants: obs-3
                            TypeQuantity(SimpleQuantity)
                            Is Modifierfalse
                            Summaryfalse
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            132. Observation.referenceRange.high
                            Definition

                            The value of the high bound of the reference range. The high bound of the reference range endpoint is inclusive of the value (e.g. reference range is >=5 - <=9). If the high bound is omitted, it is assumed to be meaningless (e.g. reference range is >= 2.3).

                            ShortHigh Range, if relevant
                            Control0..1
                            This element is affected by the following invariants: obs-3
                            TypeQuantity(SimpleQuantity)
                            Is Modifierfalse
                            Summaryfalse
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            134. Observation.referenceRange.type
                            Definition

                            Codes to indicate the what part of the targeted reference population it applies to. For example, the normal or therapeutic range.

                            ShortReference range qualifier
                            Comments

                            This SHOULD be populated if there is more than one range. If this element is not present then the normal range is assumed.

                            Control0..1
                            BindingThe codes SHOULD be taken from ObservationReferenceRangeMeaningCodes
                            (preferred to http://hl7.org/fhir/ValueSet/referencerange-meaning)

                            Code for the meaning of a reference range.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            Need to be able to say what kind of reference range this is - normal, recommended, therapeutic, etc., - for proper interpretation.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            136. Observation.referenceRange.appliesTo
                            Definition

                            Codes to indicate the target population this reference range applies to. For example, a reference range may be based on the normal population or a particular sex or race. Multiple appliesTo are interpreted as an "AND" of the target populations. For example, to represent a target population of African American females, both a code of female and a code for African American would be used.

                            ShortReference range population
                            Comments

                            This SHOULD be populated if there is more than one range. If this element is not present then the normal population is assumed.

                            Control0..*
                            BindingFor example codes, see ObservationReferenceRangeAppliesToCodes
                            (example to http://hl7.org/fhir/ValueSet/referencerange-appliesto)

                            Codes identifying the population the reference range applies to.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            Need to be able to identify the target population for proper interpretation.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            138. Observation.referenceRange.age
                            Definition

                            The age at which this reference range is applicable. This is a neonatal age (e.g. number of weeks at term) if the meaning says so.

                            ShortApplicable age range, if relevant
                            Control0..1
                            TypeRange
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            Some analytes vary greatly over age.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            140. Observation.referenceRange.text
                            Definition

                            Text based reference range in an observation which may be used when a quantitative range is not appropriate for an observation. An example would be a reference value of "Negative" or a list or table of "normals".

                            ShortText based reference range in an observation
                            Control0..1
                            Typestring
                            Is Modifierfalse
                            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                            Summaryfalse
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            142. Observation.hasMember
                            Definition

                            Used when reporting vital signs panel components.

                            ShortUsed when reporting vital signs panel components
                            Comments

                            When using this element, an observation will typically have either a value or a set of related resources, although both may be present in some cases. For a discussion on the ways Observations can assembled in groups together, see Notes below. Note that a system may calculate results from QuestionnaireResponse into a final score and represent the score as an Observation.

                            Control0..*
                            TypeReference(QuestionnaireResponse, MolecularSequence, Vital Signs Profile)
                            Is Modifierfalse
                            Summarytrue
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            144. Observation.derivedFrom
                            Definition

                            The target resource that represents a measurement from which this observation value is derived. For example, a calculated anion gap or a fetal measurement based on an ultrasound image.

                            ShortRelated measurements the observation is made from
                            Comments

                            All the reference choices that are listed in this element can represent clinical observations and other measurements that may be the source for a derived value. The most common reference will be another Observation. For a discussion on the ways Observations can assembled in groups together, see Notes below.

                            Control0..*
                            TypeReference(DocumentReference, ImagingStudy, Media, QuestionnaireResponse, MolecularSequence, Vital Signs Profile)
                            Is Modifierfalse
                            Summarytrue
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            146. Observation.component
                            Definition

                            Used when reporting systolic and diastolic blood pressure.

                            ShortUsed when reporting systolic and diastolic blood pressure.
                            Comments

                            For a discussion on the ways Observations can be assembled in groups together see Notes below.

                            Control0..*
                            TypeBackboneElement
                            Is Modifierfalse
                            Must Supporttrue
                            Summarytrue
                            Requirements

                            Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            vs-3: If there is no a value a data absent reason must be present (value.exists() or dataAbsentReason.exists())
                            148. Observation.component.id
                            Definition

                            Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                            ShortUnique id for inter-element referencing
                            Control0..1
                            Typestring
                            Is Modifierfalse
                            XML FormatIn the XML format, this property is represented as an attribute.
                            Summaryfalse
                            150. Observation.component.extension
                            Definition

                            May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                            ShortAdditional content defined by implementations
                            Comments

                            There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                            Control0..*
                            TypeExtension
                            Is Modifierfalse
                            Summaryfalse
                            Alternate Namesextensions, user content
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                            152. Observation.component.modifierExtension
                            Definition

                            May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

                            Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

                            ShortExtensions that cannot be ignored even if unrecognized
                            Comments

                            There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                            Control0..*
                            TypeExtension
                            Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
                            Summarytrue
                            Requirements

                            Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

                            Alternate Namesextensions, user content, modifiers
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                            154. Observation.component.code
                            Definition

                            Describes what was observed. Sometimes this is called the observation "code".

                            ShortType of component observation (code / type)
                            Comments

                            All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

                            Control1..1
                            BindingUnless not suitable, these codes SHALL be taken from VitalSigns
                            (extensible to http://hl7.org/fhir/ValueSet/observation-vitalsignresult)

                            This identifies the vital sign result type.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Must Supporttrue
                            Summarytrue
                            Requirements

                            Knowing what kind of observation is being made is essential to understanding the observation.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            156. Observation.component.value[x]
                            Definition

                            Vital Sign Value recorded with UCUM.

                            ShortVital Sign Value recorded with UCUM
                            Comments

                            Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

                            Control0..1
                            This element is affected by the following invariants: vs-3
                            BindingUnless not suitable, these codes SHALL be taken from VitalSignsUnits
                            (extensible to http://hl7.org/fhir/ValueSet/ucum-vitals-common|4.0.1)

                            Common UCUM units for recording Vital Signs.

                            TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
                            [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                            Is Modifierfalse
                            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                            Must Supporttrue
                            Must Support TypesNo must-support rules about the choice of types/profiles
                            Summarytrue
                            Requirements
                            1. SHALL contain exactly one [1..1] value with @xsi:type="PQ" (CONF:7305).
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            158. Observation.component.dataAbsentReason
                            Definition

                            Provides a reason why the expected value in the element Observation.component.value[x] is missing.

                            ShortWhy the component result is missing
                            Comments

                            "Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

                            The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

                            Control0..1
                            This element is affected by the following invariants: obs-6, vs-3
                            BindingUnless not suitable, these codes SHALL be taken from DataAbsentReason
                            (extensible to http://hl7.org/fhir/ValueSet/data-absent-reason)

                            Codes specifying why the result (Observation.value[x]) is missing.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Must Supporttrue
                            Summaryfalse
                            Requirements

                            For many results it is necessary to handle exceptional values in measurements.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            160. Observation.component.interpretation
                            Definition

                            A categorical assessment of an observation value. For example, high, low, normal.

                            ShortHigh, low, normal, etc.
                            Comments

                            Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

                            Control0..*
                            BindingUnless not suitable, these codes SHALL be taken from ObservationInterpretationCodes
                            (extensible to http://hl7.org/fhir/ValueSet/observation-interpretation)

                            Codes identifying interpretations of observations.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

                            Alternate NamesAbnormal Flag
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            162. Observation.component.referenceRange
                            Definition

                            Guidance on how to interpret the value by comparison to a normal or recommended range.

                            ShortProvides guide for interpretation of component result
                            Comments

                            Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

                            Control0..*
                            TypeSeettp://hl7.org/fhir/StructureDefinition/Observation#Observation.referenceRange
                            Is Modifierfalse
                            Summaryfalse
                            Requirements

                            Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))