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Orders and Observations Work Group Maturity Level: 1Trial Use Use Context: Any

Definitions for the oxygensat Profile.

Observation
Element IdObservation
Definition

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

Control0..*
Alternate NamesVital Signs, Measurement, Results, Tests
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.

InvariantsDefined on this element
dom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (xpath: not(parent::f:contained and f:contained))
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 (xpath: not(exists(for $contained in f:contained return $contained[not(parent::*/descendant::f:reference/@value=concat('#', $contained/*/id/@value) or descendant::f:reference[@value='#'])])))
dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (xpath: not(exists(f:contained/*/f:meta/f:versionId)) and not(exists(f:contained/*/f:meta/f:lastUpdated)))
dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (xpath: not(exists(f:contained/*/f:meta/f:security)))
dom-6: A resource should have narrative for robust management (xpath: exists(f:text/h:div))
obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present (xpath: not(exists(f:dataAbsentReason)) or (not(exists(*[starts-with(local-name(.), 'value')]))))
obs-7: If Observation.code is the same as a Observation.component.code then the value element associated with the code SHALL NOT be present (xpath: not(f:*[starts-with(local-name(.), 'value')] and (for $coding in f:code/f:coding return f:component/f:code/f:coding[f:code/@value=$coding/f:code/@value] [f:system/@value=$coding/f:system/@value])))
vs-2: If there is no component or hasMember element then either a value[x] or a data absent reason must be present. (xpath: f:component or f:memberOF or f:*[starts-with(local-name(.), 'value')] or f:dataAbsentReason)
Observation.id
Element IdObservation.id
Definition

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

Control0..1
Typeid
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.

Observation.meta
Element IdObservation.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.

Control0..1
TypeMeta
Observation.implicitRules
Element IdObservation.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.

Control0..1
Typeuri
Is Modifiertrue (Reason: 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)
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.

Observation.language
Element IdObservation.language
Definition

The base language in which the resource is written.

Control0..1
Terminology BindingA human language.
The codes SHALL be taken from Common Languages; other codes may be used where these codes are not suitable
Typecode
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).

Observation.text
Element IdObservation.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.

Control0..1
TypeNarrative
Alternate Namesnarrative, html, xhtml, display
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.

Observation.contained
Element IdObservation.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.

Control0..*
TypeResource
Alternate Namesinline resources, anonymous resources, contained 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.

Observation.extension
Element IdObservation.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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

Observation.modifierExtension
Element IdObservation.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. 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).

Control0..*
TypeExtension
Is Modifiertrue (Reason: Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them)
Alternate Namesextensions, user content
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.

Observation.identifier
Element IdObservation.identifier
Definition

A unique identifier assigned to this observation.

Control0..*
TypeIdentifier
Requirements

Allows observations to be distinguished and referenced.

Observation.basedOn
Element IdObservation.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.

Control0..*
TypeReference(CarePlan)
Requirements

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

Alternate NamesFulfills
Observation.partOf
Element IdObservation.partOf
Definition

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

Control0..*
TypeReference(MedicationAdministration)
Alternate NamesContainer
Comments

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

Observation.status
Element IdObservation.status
Definition

The status of the result value.

Control1..1
Terminology Bindingnull
The codes SHALL be taken from ObservationStatus
Typecode
Is Modifiertrue (Reason: 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)
Must Supporttrue
Requirements

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

Comments

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

Observation.category
Element IdObservation.category
Definition

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

Control1..*
Terminology BindingCodes for high level observation categories.
The codes SHOULD be taken from Observation Category Codes
TypeCodeableConcept
Must Supporttrue
Requirements

Used for filtering what observations are retrieved and displayed.

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.

SlicingThis element introduces a set of slices. The slicing rules are:
  • unordered
  • Open
  • discriminators: value:coding.code, value:coding.system
Observation.category(VSCat)
Element IdObservation.category:VSCat
Definition

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

Control1..1
Terminology BindingCodes for high level observation categories.
The codes SHOULD be taken from Observation Category Codes
TypeCodeableConcept
Must Supporttrue
Requirements

Used for filtering what observations are retrieved and displayed.

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.

Observation.category.id
Element IdObservation.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.

Control0..1
Typestring
Observation.category.extension
Element IdObservation.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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

SlicingThis element introduces a set of slices. The slicing rules are:
  • unordered
  • Open
  • discriminators: value:url
Observation.category.coding
Element IdObservation.category:VSCat.coding
Definition

A reference to a code defined by a terminology system.

Control1..*
TypeCoding
Must Supporttrue
Requirements

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

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.

Observation.category.coding.id
Element IdObservation.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.

Control0..1
Typestring
Observation.category.coding.extension
Element IdObservation.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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

SlicingThis element introduces a set of slices. The slicing rules are:
  • unordered
  • Open
  • discriminators: value:url
Observation.category.coding.system
Element IdObservation.category:VSCat.coding.system
Definition

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

Control1..1
Typeuri
Must Supporttrue
Requirements

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

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.

Fixed Valuehttp://terminology.hl7.org/CodeSystem/observation-category
Observation.category.coding.version
Element IdObservation.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.

Control0..1
Typestring
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.

Observation.category.coding.code
Element IdObservation.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).

Control1..1
Typecode
Must Supporttrue
Requirements

Need to refer to a particular code in the system.

Fixed Valuevital-signs
Observation.category.coding.display
Element IdObservation.category:VSCat.coding.display
Definition

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

Control0..1
Typestring
Requirements

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

Observation.category.coding.userSelected
Element IdObservation.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).

Control0..1
Typeboolean
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.

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.

Observation.category.text
Element IdObservation.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.

Control0..1
Typestring
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.

Comments

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

Observation.code
Element IdObservation.code
Definition

Oxygen Saturation.

Control1..1
Terminology BindingThis identifies the vital sign result type.
The codes SHALL be taken from Vital Signs; other codes may be used where these codes are not suitable
TypeCodeableConcept
Must Supporttrue
Requirements
  1. SHALL contain exactly one [1..1] code, where the @code SHOULD be selected from ValueSet HITSP Vital Sign Result Type 2.16.840.1.113883.3.88.12.80.62 DYNAMIC (CONF:7301).
Alternate NamesName, Test
Comments

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

Observation.code.id
Element IdObservation.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.

Control0..1
Typestring
Observation.code.extension
Element IdObservation.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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

SlicingThis element introduces a set of slices. The slicing rules are:
  • unordered
  • Open
  • discriminators: value:url
Observation.code.coding
Element IdObservation.code.coding
Definition

A reference to a code defined by a terminology system.

Control0..*
TypeCoding
Requirements

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

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.

SlicingThis element introduces a set of slices. The slicing rules are:
  • unordered
  • Open
  • discriminators: value:code, value:system
Observation.code.coding(OxygenSatCode)
Element IdObservation.code.coding:OxygenSatCode
Definition

A reference to a code defined by a terminology system.

Control1..1
TypeCoding
Requirements

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

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.

Observation.code.coding.id
Element IdObservation.code.coding:OxygenSatCode.id
Definition

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

Control0..1
Typestring
Observation.code.coding.extension
Element IdObservation.code.coding:OxygenSatCode.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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

SlicingThis element introduces a set of slices. The slicing rules are:
  • unordered
  • Open
  • discriminators: value:url
Observation.code.coding.system
Element IdObservation.code.coding:OxygenSatCode.system
Definition

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

Control1..1
Typeuri
Requirements

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

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.

Fixed Valuehttp://loinc.org
Observation.code.coding.version
Element IdObservation.code.coding:OxygenSatCode.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.

Control0..1
Typestring
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.

Observation.code.coding.code
Element IdObservation.code.coding:OxygenSatCode.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).

Control1..1
Typecode
Requirements

Need to refer to a particular code in the system.

Fixed Value2708-6
Observation.code.coding.display
Element IdObservation.code.coding:OxygenSatCode.display
Definition

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

Control0..1
Typestring
Requirements

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

Observation.code.coding.userSelected
Element IdObservation.code.coding:OxygenSatCode.userSelected
Definition

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

Control0..1
Typeboolean
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.

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.

Observation.code.text
Element IdObservation.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.

Control0..1
Typestring
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.

Comments

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

Observation.subject
Element IdObservation.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.

Control1..1
TypeReference(Patient)
Must Supporttrue
Requirements

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

Observation.focus
Element IdObservation.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.

Control0..*
TypeReference(Resource)
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.

Observation.context
Element IdObservation.context
Definition

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

Control0..1
TypeReference(Encounter)
Requirements

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

Alternate NamesEncounter
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 or episode but still be tied to the context of the encounter or episode (e.g. pre-admission laboratory tests).

Observation.effective[x]
Element IdObservation.effective[x]
Definition

Often just a dateTime for Vital Signs.

Control1..1
TypeChoice of: dateTime, Period
[x] NoteSee Choice of Data Types for further information about how to use [x]
Must Supporttrue
Requirements

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

Alternate NamesOccurrence
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.

InvariantsDefined on this element
vs-1: Datetime must be at least to day. (xpath: f:matches(effectiveDateTime,/\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d([+-][0-2]\d:[0-5]\d|Z)/))
Observation.issued
Element IdObservation.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.

Control0..1
Typeinstant
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.

Observation.performer
Element IdObservation.performer
Definition

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

Control0..*
TypeReference(Practitioner)
Requirements

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

Observation.value[x]
Element IdObservation.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.

Control0..1 This element is affected by the following invariants: obs-7
TypeQuantity
[x] NoteSee Choice of Data Types for further information about how to use [x]
Must Supporttrue
Requirements
  1. SHALL contain exactly one [1..1] value with @xsi:type="PQ" (CONF:7305).
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.

Observation.value[x].id
Element IdObservation.value[x].id
Definition

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

Control0..1
Typestring
Observation.value[x].extension
Element IdObservation.value[x].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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

SlicingThis element introduces a set of slices. The slicing rules are:
  • unordered
  • Open
  • discriminators: value:url
Observation.value[x].value
Element IdObservation.value[x].value
Definition

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

Control1..1
Typedecimal
Must Supporttrue
Requirements

Precision is handled implicitly in almost all cases of measurement.

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).

Observation.value[x].comparator
Element IdObservation.value[x].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.

Control0..1
Terminology BindingHow the Quantity should be understood and represented.
The codes SHALL be taken from QuantityComparator
Typecode
Is Modifiertrue (Reason: This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value)
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
Observation.value[x].unit
Element IdObservation.value[x].unit
Definition

A human-readable form of the unit.

Control1..1
Typestring
Must Supporttrue
Requirements

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

Observation.value[x].system
Element IdObservation.value[x].system
Definition

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

Control1..1 This element is affected by the following invariants: qty-3
Typeuri
Must Supporttrue
Requirements

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

Fixed Valuehttp://unitsofmeasure.org
Observation.value[x].code
Element IdObservation.value[x].code
Definition

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

Control1..1
Typecode
Must Supporttrue
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.

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.

Fixed Value%
Observation.dataAbsentReason
Element IdObservation.dataAbsentReason
Definition

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

Control0..1 This element is affected by the following invariants: obs-6
Terminology BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Must Supporttrue
Requirements

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

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.

Observation.interpretation
Element IdObservation.interpretation
Definition

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

Control0..*
Terminology BindingCodes identifying interpretations of observations.
The codes SHALL be taken from Observation Interpretation Codes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

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

Alternate NamesAbnormal Flag
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 often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.comment
Element IdObservation.comment
Definition

Comments about the test result value may include statements about significant, unexpected or unreliable results values, or information about the its source when this is relevant to its interpretation.

Control0..1
Typestring
Requirements

Need to be able to provide free text additional information.

Observation.bodySite
Element IdObservation.bodySite
Definition

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

Control0..1
Terminology BindingCodes describing anatomical locations. May include laterality.
For example codes, see SNOMED CT Body Structures
TypeCodeableConcept
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 bodyStructure.

Observation.method
Element IdObservation.method
Definition

Indicates the mechanism used to perform the observation.

Control0..1
Terminology BindingMethods for simple observations.
For example codes, see Observation Methods
TypeCodeableConcept
Requirements

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

Comments

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

Observation.specimen
Element IdObservation.specimen
Definition

The specimen that was used when this observation was made.

Control0..1
TypeReference(Specimen)
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).

Observation.device
Element IdObservation.device
Definition

The device used to generate the observation data.

Control0..1
TypeReference(Device)
Comments

An extension should be used if further typing of the device is needed. Devices used to support obtaining an observation can be represented using an extension or the Provenance resource. (e.g., a device gateway such as a smart phone).

Observation.referenceRange
Element IdObservation.referenceRange
Definition

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

Control0..*
TypeBackboneElement
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.

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.

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (xpath: @value|f:*|h:div)
obs-3: Must have at least a low or a high or text (xpath: (exists(f:low) or exists(f:high)or exists(f:text)))
Observation.referenceRange.id
Element IdObservation.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.

Control0..1
Typestring
Observation.referenceRange.extension
Element IdObservation.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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

Observation.referenceRange.modifierExtension
Element IdObservation.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. 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).

Control0..*
TypeExtension
Is Modifiertrue (Reason: Modifier extensions are expected to modify the meaning or interpretation of the element that contains them)
Alternate Namesextensions, user content, modifiers
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.

Observation.referenceRange.low
Element IdObservation.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).

Control0..1 This element is affected by the following invariants: obs-3
TypeQuantity(SimpleQuantity)
Observation.referenceRange.high
Element IdObservation.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).

Control0..1 This element is affected by the following invariants: obs-3
TypeQuantity(SimpleQuantity)
Observation.referenceRange.type
Element IdObservation.referenceRange.type
Definition

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

Control0..1
Terminology BindingCode for the meaning of a reference range.
The codes SHOULD be taken from Observation Reference Range Meaning Codes
TypeCodeableConcept
Requirements

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

Comments

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

Observation.referenceRange.appliesTo
Element IdObservation.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.

Control0..*
Terminology BindingCodes identifying the population the reference range applies to.
For example codes, see Observation Reference Range Applies To Codes
TypeCodeableConcept
Requirements

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

Comments

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

Observation.referenceRange.age
Element IdObservation.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.

Control0..1
TypeRange
Requirements

Some analytes vary greatly over age.

Observation.referenceRange.text
Element IdObservation.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".

Control0..1
Typestring
Observation.hasMember
Element IdObservation.hasMember
Definition

Used when reporting vital signs panel components.

Control0..*
TypeReference(QuestionnaireResponse)
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.

Observation.derivedFrom
Element IdObservation.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.

Control0..*
TypeReference(DocumentReference)
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.

Observation.component
Element IdObservation.component
Definition

Used when reporting systolic and diastolic blood pressure.

Control0..*
TypeBackboneElement
Must Supporttrue
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.

Comments

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

InvariantsDefined on this element
ele-1: All FHIR elements must have a @value or children (xpath: @value|f:*|h:div)
vs-3: If there is no a value a data absent reason must be present (xpath: f:*[starts-with(local-name(.), 'value')] or f:dataAbsentReason)
Observation.component.id
Element IdObservation.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.

Control0..1
Typestring
Observation.component.extension
Element IdObservation.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.

Control0..*
TypeExtension
Alternate Namesextensions, user content
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.

Observation.component.modifierExtension
Element IdObservation.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. 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).

Control0..*
TypeExtension
Is Modifiertrue (Reason: Modifier extensions are expected to modify the meaning or interpretation of the element that contains them)
Alternate Namesextensions, user content, modifiers
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.

Observation.component.code
Element IdObservation.component.code
Definition

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

Control1..1
Terminology BindingThis identifies the vital sign result type.
The codes SHALL be taken from Vital Signs; other codes may be used where these codes are not suitable
TypeCodeableConcept
Must Supporttrue
Requirements

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

Comments

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

Observation.component.value[x]
Element IdObservation.component.value[x]
Definition

Vital Sign Value recorded with UCUM.

Control0..1
Terminology BindingCommon UCUM units for recording Vital Signs.
The codes SHALL be taken from Vital Signs Units
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]
Must Supporttrue
Requirements
  1. SHALL contain exactly one [1..1] value with @xsi:type="PQ" (CONF:7305).
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.

Observation.component.dataAbsentReason
Element IdObservation.component.dataAbsentReason
Definition

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

Control0..1 This element is affected by the following invariants: obs-6
Terminology BindingCodes specifying why the result (`Observation.value[x]`) is missing.
The codes SHALL be taken from DataAbsentReason; other codes may be used where these codes are not suitable
TypeCodeableConcept
Must Supporttrue
Requirements

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

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.

Observation.component.interpretation
Element IdObservation.component.interpretation
Definition

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

Control0..*
Terminology BindingCodes identifying interpretations of observations.
The codes SHALL be taken from Observation Interpretation Codes; other codes may be used where these codes are not suitable
TypeCodeableConcept
Requirements

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

Alternate NamesAbnormal Flag
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 often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Observation.component.referenceRange
Element IdObservation.component.referenceRange
Definition

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

Control0..*
TypeSee Observation.referenceRange
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.

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.