US Core Implementation Guide
7.0.0 - STU7 United States of America flag

US Core Implementation Guide, published by HL7 International / Cross-Group Projects. This guide is not an authorized publication; it is the continuous build for version 7.0.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/US-Core/ and changes regularly. See the Directory of published versions

Resource Profile: USCoreCareExperiencePreferenceProfile - Detailed Descriptions

Page standards status: Trial-use Maturity Level: 3

Definitions for the us-core-care-experience-preference resource profile.

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

0. Observation
ShortUS Core Care Experience Preference Profile
2. Observation.status
Must Supporttrue
4. Observation.category
Must Supporttrue
SlicingThis element introduces a set of slices on Observation.category. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • pattern @ $this
  • 6. Observation.category:us-core
    Slice Nameus-core
    Control0..1
    Must Supporttrue
    Pattern Value{
      "coding" : [{
        "system" : "http://hl7.org/fhir/us/core/CodeSystem/us-core-category",
        "code" : "care-experience-preference"
      }]
    }
    8. Observation.code
    ShortCare experience preferences code
    TypeCodeableConcept
    Must Supporttrue
    Pattern Value{
      "coding" : [{
        "system" : "http://loinc.org",
        "code" : "95541-9"
      }]
    }
    10. Observation.subject
    Control1..?
    TypeReference(US Core Patient Profile)
    Must Supporttrue
    12. Observation.effective[x]
    Definition

    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".

    Comments

    At least a date should be present unless this observation is a historical report.

    TypeChoice of: dateTime, Period, Timing, instant
    [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Must Supporttrue
    Must Support TypesdateTime
    14. Observation.value[x]
    TypeChoice of: string, CodeableConcept, Quantity, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
    [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Must Supporttrue
    Must Support TypesChoice of: string, CodeableConcept

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

    0. Observation
    Definition

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

    ShortUS Core Care Experience Preference 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())
    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.

    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)

    Codes providing the status of an observation.

    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.

    Control0..*
    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:
    • pattern @ $this
    • 10. Observation.category:us-core
      Slice Nameus-core
      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.

      Control0..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.

      Pattern Value{
        "coding" : [{
          "system" : "http://hl7.org/fhir/us/core/CodeSystem/us-core-category",
          "code" : "care-experience-preference"
        }]
      }
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      12. Observation.code
      Definition

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

      ShortCare experience preferences codeType of observation (code / type)
      Comments

      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
      BindingFor example codes, see LOINCCodeshttp://hl7.org/fhir/ValueSet/observation-codes
      (example to http://hl7.org/fhir/ValueSet/observation-codes)

      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.

      Alternate NamesName
      Pattern Value{
        "coding" : [{
          "system" : "http://loinc.org",
          "code" : "95541-9"
        }]
      }
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      14. 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(US Core Patient Profile, 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()))
      16. Observation.effective[x]
      Definition

      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".


      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.

      ShortClinically relevant time/time-period for observation
      Comments

      At least a date should be present unless this observation is a historical report.


      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.

      Control0..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 TypesdateTime
      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()))
      18. Observation.value[x]
      Definition

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

      ShortActual 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.

      Control0..1
      This element is affected by the following invariants: obs-7
      TypeChoice of: string, CodeableConcept, Quantity, 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 TypesChoice of: string, CodeableConcept
      Summarytrue
      Requirements

      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()))

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

      0. Observation
      Definition

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

      ShortUS Core Care Experience Preference 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())
      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)

      Codes providing the status of an observation.

      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.

      Control0..*
      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:
      • pattern @ $this
      • 28. Observation.category:us-core
        Slice Nameus-core
        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.

        Control0..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.

        Pattern Value{
          "coding" : [{
            "system" : "http://hl7.org/fhir/us/core/CodeSystem/us-core-category",
            "code" : "care-experience-preference"
          }]
        }
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        30. Observation.code
        Definition

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

        ShortCare experience preferences code
        Comments

        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
        BindingFor example codes, see LOINCCodes
        (example to http://hl7.org/fhir/ValueSet/observation-codes)

        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.

        Alternate NamesName
        Pattern Value{
          "coding" : [{
            "system" : "http://loinc.org",
            "code" : "95541-9"
          }]
        }
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        32. 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(US Core Patient Profile)
        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()))
        34. 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()))
        36. 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()))
        38. Observation.effective[x]
        Definition

        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".

        ShortClinically relevant time/time-period for observation
        Comments

        At least a date should be present unless this observation is a historical report.

        Control0..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 TypesdateTime
        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()))
        40. 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()))
        42. 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()))
        44. Observation.value[x]
        Definition

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

        ShortActual 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.

        Control0..1
        This element is affected by the following invariants: obs-7
        TypeChoice of: string, CodeableConcept, Quantity, 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 TypesChoice of: string, CodeableConcept
        Summarytrue
        Requirements

        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()))
        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
        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
        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.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()))
        50. 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()))
        52. 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()))
        54. 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()))
        56. 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()))
        58. 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()))
        60. 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())
        62. 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
        64. 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())
        66. 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())
        68. 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()))
        70. 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()))
        72. 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()))
        74. 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()))
        76. 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()))
        78. 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()))
        80. Observation.hasMember
        Definition

        This observation is a group observation (e.g. a battery, a panel of tests, a set of vital sign measurements) that includes the target as a member of the group.

        ShortRelated resource that belongs to the Observation group
        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(Observation, QuestionnaireResponse, MolecularSequence)
        Is Modifierfalse
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        82. 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, Observation, MolecularSequence)
        Is Modifierfalse
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        84. Observation.component
        Definition

        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.

        ShortComponent results
        Comments

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

        Control0..*
        TypeBackboneElement
        Is Modifierfalse
        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()))
        86. 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
        88. 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())
        90. 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())
        92. 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
        BindingFor example codes, see LOINCCodes
        (example to http://hl7.org/fhir/ValueSet/observation-codes)

        Codes identifying names of simple observations.

        TypeCodeableConcept
        Is Modifierfalse
        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()))
        94. Observation.component.value[x]
        Definition

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

        ShortActual 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.

        Control0..1
        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
        Summarytrue
        Requirements

        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()))
        96. 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
        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
        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()))
        98. 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()))
        100. 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()))