Clinical Practice Guidelines
2.0.0-ballot - ballot International flag

Clinical Practice Guidelines, published by HL7 International / Clinical Decision Support. This guide is not an authorized publication; it is the continuous build for version 2.0.0-ballot built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/cqf-recommendations/ and changes regularly. See the Directory of published versions

Resource Profile: CHFPotassium - Detailed Descriptions

Active as of 2023-12-19

Definitions for the chf-potassium resource profile.

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

0. Observation
2. Observation.code
Definition

Potassium (in meq/L).

ShortPotassium
4. Observation.code.coding
Control1..?
SlicingThis element introduces a set of slices on Observation.code.coding. The slices are unordered and Open, and can be differentiated using the following discriminators:
  • value @ code
  • value @ system
6. Observation.code.coding:PotassiumCode
Slice NamePotassiumCode
Control1..1
8. Observation.code.coding:PotassiumCode.system
Control1..?
Fixed Valuehttp://loinc.org
10. Observation.code.coding:PotassiumCode.code
Control1..?
Fixed Value86919-8
12. Observation.value[x]
[x] NoteSee Choice of Data Types for further information about how to use [x]
SlicingThis element introduces a set of slices on Observation.value[x]. The slices are unordered and Open, and can be differentiated using the following discriminators:
  • type @ $this
14. Observation.value[x]:valueQuantity
Slice NamevalueQuantity
Control0..1
TypeQuantity
[x] NoteSee Choice of Data Types for 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

Percent saturation

Short%
Control1..?
Fixed Valuemeq/L

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

0. Observation
Definition

The FHIR Vitals Signs profile sets minimum expectations for the Observation Resource to record, search and fetch the vital signs associated with a patient.


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

ShortFHIR Vital Signs 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
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

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 are unordered 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

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

Potassium (in meq/L).


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

ShortPotassiumType 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
BindingUnless not suitable, these codes SHALL be taken from For example codes, see VitalSignshttp://hl7.org/fhir/ValueSet/observation-codes

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
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 are unordered and Open, and can be differentiated using the following discriminators:
  • value @ code
  • value @ system
22. Observation.code.coding:PotassiumCode
Slice NamePotassiumCode
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:PotassiumCode.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:PotassiumCode.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 Value86919-8
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] NoteSee Choice of Data Types for 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] NoteSee Choice of Data Types for 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 are unordered 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] NoteSee Choice of Data Types for 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

How the Quantity should be understood and represented.

Typecode
Is Modifiertrue because This is labeled as &quot;Is Modifier&quot; 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

Percent saturation


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

Short%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
Typecode
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
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.

Fixed Valuemeq/L
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

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

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
BindingThe codes SHALL be taken from For codes, see VitalSignsUnits

Common UCUM units for recording Vital Signs.

TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
[x] NoteSee Choice of Data Types for 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

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

The FHIR Vitals Signs profile sets minimum expectations for the Observation Resource to record, search and fetch the vital signs associated with a patient.

ShortFHIR Vital Signs 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

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
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

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 are unordered 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

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 are unordered 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 are unordered 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 versionId, 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

Potassium (in meq/L).

ShortPotassium
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
BindingUnless not suitable, these codes SHALL be taken from VitalSigns

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
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 are unordered 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 are unordered and Open, and can be differentiated using the following discriminators:
  • value @ code
  • value @ system
60. Observation.code.coding:PotassiumCode
Slice NamePotassiumCode
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:PotassiumCode.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:PotassiumCode.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 are unordered and Open, and can be differentiated using the following discriminators:
  • value @ url
66. Observation.code.coding:PotassiumCode.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:PotassiumCode.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 versionId, 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:PotassiumCode.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 Value86919-8
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
72. Observation.code.coding:PotassiumCode.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:PotassiumCode.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] NoteSee Choice of Data Types for 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] NoteSee Choice of Data Types for 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 are unordered 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] NoteSee Choice of Data Types for 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 are unordered 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

How the Quantity should be understood and represented.

Typecode
Is Modifiertrue because This is labeled as &quot;Is Modifier&quot; 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

Percent saturation

Short%
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
Typecode
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
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.

Fixed Valuemeq/L
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

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

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

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

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

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

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

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
BindingThe codes SHALL be taken from VitalSignsUnits

Common UCUM units for recording Vital Signs.

TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
[x] NoteSee Choice of Data Types for 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

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

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..*
TypeSee ttp://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()))