Canadian Baseline
1.2.0 - CI Build Canada flag

Canadian Baseline, published by HL7 Canada - FHIR Implementation Work Group. This guide is not an authorized publication; it is the continuous build for version 1.2.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7-Canada/ca-baseline/ and changes regularly. See the Directory of published versions

Resource Profile: Observation Profile (General)

Official URL: http://hl7.org/fhir/ca/baseline/StructureDefinition/profile-observation Version: 1.2.0
Draft as of 2024-08-09 Computable Name: ObservationProfile

Proposed constraints on the Observation Resource for general use. This profile sets minimum expectations for the Observation resource to represent various observations if no other, more specific profile is applicable. An observation is a measurement or assertion about a subject (person, group, device, location, or another subject).

CA Baseline Observation (General Use) Profile

While this profile does not currently apply MS constraints on the hasMember or component elements, this profile is seeking community and implementer feedback on how both elements are being used to assess whether consistent patterns can be identified for use in the Canadian landscape.
Feedback can be provided through the Simplifier issue log for this profile.

This profile sets minimum expectations for the Observation resource to represent various observations if no other, more specific profile is applicable. An observation is a measurement or assertion about a subject (person, group, device, location, or another subject).

This profile defines localization concepts for use in the Canadian context.

Mandatory Data Elements

All elements or attributes within the FHIR specification have cardinality as part of their definition - a minimum number of required appearances and a maximum number of allowable appearances.

Most elements in the FHIR specification have a minimum cardinality of 0, so most elements are not required and subsequently they may be missing from a resource when it is exchanged between systems.

Required elements in the Observation (General Use) profile:

  • status of the result value (Observation.status)
  • type of observation (Observation.code)
  • subject of the observation (Observation.subject)

Must Support Data Elements

Some elements are marked as Must Support. This means that implementations generating, receiving, or otherwise using resources with Must Support elements SHALL provide support for those elements in some meaningful way (see Must Support definition).

The following elements are marked as Must Support in the Observation (General Use) profile:

Must Support elements:

  • category
  • code
  • reference to a subject (Observation.subject)
  • effective data
  • value
  • component code (if implementer supports component)
  • component value (if implementer supports component)

Usage Note

Observation (General Use) is intended to capture data associated with most observations; it is not intended to capture data in some cases where a more appropriate profile is applicable (see below). Data typically consists of measurements or assertions about a subject. Observation (General Use) can capture data in eclectic use cases as it incorporates multiple categories of observations and datatypes. Observation (General Use) can capture data such as:

  • Clinical observations such as clinical finding, diagnosis, disorder
  • Demographic information
  • Device measurements
  • Determinants of health such as housing status, income, family support

Observation (General Use) should not be used if one of the following profiles is applicable:

  • Observation (Laboratory Results)
  • Observation (Vitals)

Usage:

Formal Views of Profile Content

Description of Profiles, Differentials, Snapshots and how the different presentations work.

NameFlagsCard.TypeDescription & Constraintsdoco
.. Observation C 0..* Observation Observation Profile
dom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources
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
dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated
dom-5: If a resource is contained in another resource, it SHALL NOT have a security label
dom-6: A resource should have narrative for robust management
obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present
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
... implicitRules ?!Σ 0..1 uri A set of rules under which this content was created
ele-1: All FHIR elements must have a @value or children
... modifierExtension ?! 0..* Extension Extensions that cannot be ignored
ele-1: All FHIR elements must have a @value or children
ext-1: Must have either extensions or value[x], not both
... status ?!Σ 1..1 code registered | preliminary | final | amended +
Binding: ObservationStatus (required): Codes providing the status of an observation.


ele-1: All FHIR elements must have a @value or children
... code SΣ 1..1 CodeableConcept Type of observation (code / type)
Binding: LOINCCodes (preferred): LOINC codes identifying names of simple observations.


ele-1: All FHIR elements must have a @value or children
... subject SΣ 1..1 Reference(Patient Profile | Group | Device | Location) Who and/or what the observation is about
ele-1: All FHIR elements must have a @value or children
... effective[x] SΣ 0..1 Clinically relevant time/time-period for observation
ele-1: All FHIR elements must have a @value or children
.... effectiveDateTime dateTime
.... effectivePeriod Period
... value[x] SΣC 0..1 Actual result
ele-1: All FHIR elements must have a @value or children
.... valueQuantity Quantity
.... valueCodeableConcept CodeableConcept
.... valueString string
.... valueBoolean boolean
.... valueInteger integer
.... valueRange Range
.... valueRatio Ratio
.... valueSampledData SampledData
.... valueTime time
.... valueDateTime dateTime
.... valuePeriod Period
... dataAbsentReason C 0..1 CodeableConcept Why the result is missing
Binding: DataAbsentReason (extensible): Codes specifying why the result (Observation.value[x]) is missing.


ele-1: All FHIR elements must have a @value or children
... component Σ 0..* BackboneElement Component results
ele-1: All FHIR elements must have a @value or children
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
ele-1: All FHIR elements must have a @value or children
ext-1: Must have either extensions or value[x], not both
.... code SΣ 1..1 CodeableConcept Type of component observation (code / type)
Binding: LOINCCodes (preferred): LOINC codes identifying names of simple observations.


ele-1: All FHIR elements must have a @value or children
.... value[x] SΣ 0..1 Actual component result
ele-1: All FHIR elements must have a @value or children
..... valueQuantity Quantity
..... valueCodeableConcept CodeableConcept
..... valueString string
..... valueBoolean boolean
..... valueInteger integer
..... valueRange Range
..... valueRatio Ratio
..... valueSampledData SampledData
..... valueTime time
..... valueDateTime dateTime
..... valuePeriod Period
.... dataAbsentReason C 0..1 CodeableConcept Why the component result is missing
Binding: DataAbsentReason (extensible): Codes specifying why the result (Observation.value[x]) is missing.


ele-1: All FHIR elements must have a @value or children

doco Documentation for this format

Terminology Bindings

PathConformanceValueSetURI
Observation.statusrequiredObservationStatus
http://hl7.org/fhir/ValueSet/observation-status|4.0.1
from the FHIR Standard
Observation.categorypreferredObservationCategoryCodes
http://hl7.org/fhir/ValueSet/observation-category
from the FHIR Standard
Observation.codepreferredLOINCCodes (a valid code from LOINC)
http://hl7.org/fhir/ValueSet/observation-codes
from the FHIR Standard
Observation.dataAbsentReasonextensibleDataAbsentReason
http://hl7.org/fhir/ValueSet/data-absent-reason
from the FHIR Standard
Observation.component.codepreferredLOINCCodes (a valid code from LOINC)
http://hl7.org/fhir/ValueSet/observation-codes
from the FHIR Standard
Observation.component.dataAbsentReasonextensibleDataAbsentReason
http://hl7.org/fhir/ValueSet/data-absent-reason
from the FHIR Standard

Constraints

IdGradePath(s)DetailsRequirements
dom-2errorObservationIf the resource is contained in another resource, it SHALL NOT contain nested Resources
: contained.contained.empty()
dom-3errorObservationIf 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-4errorObservationIf 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-5errorObservationIf a resource is contained in another resource, it SHALL NOT have a security label
: contained.meta.security.empty()
dom-6best practiceObservationA resource should have narrative for robust management
: text.`div`.exists()
ele-1error**ALL** elementsAll FHIR elements must have a @value or children
: hasValue() or (children().count() > id.count())
ext-1error**ALL** extensionsMust have either extensions or value[x], not both
: extension.exists() != value.exists()
obs-6errorObservationdataAbsentReason SHALL only be present if Observation.value[x] is not present
: dataAbsentReason.empty() or value.empty()
obs-7errorObservationIf 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()

 

Other representations of profile: CSV, Excel, Schematron

Notes:

Using codes in Observation

Additional codes that translate or map to the Observation code or category codes are allowed (see CodeableConcept data type).

Examples:

  • providing both a local code and LOINC code
  • providing more specific category codes
  • providing a SNOMED CT concept
  • providing system specific codes

Category

The Observation.category specifies a code that classifies the type of observation. The Observation.category element is a CodeableConcept data type, and more than one code is allowed.

For interoperability reasons, one of the codes SHOULD be from the FHIR standard defined Observation Category Codes.

Local codes are allowed as well. In the case of using local codes, in order to classify the type of observation both category.coding.system and category.coding.code SHOULD be provided.

Code

The Observation.code element describes what was observed. Sometimes this is called the observation "name".

The pan-Canadian LOINC Observation Code Database (pCLOCD) is recommended for use in the Canadian context. pCLOCD Code System URI is https://fhir.infoway-inforoute.ca/CodeSystem/pCLOCD

value[x] and dataAbsentReason

Observation (General Use) uses a name-value pair to code data. When the value for the actual observation is not known, i.e., the value for Observation.value[x] is not available, then Observation.value[x] will not be present and the Observation.dataAbsentReason SHALL be present and will provide a reason why the expected value is missing. Also, the Observation.dataAbsentReason SHALL only be present if and only if the value for Observation.value[x] is not present.

The same rule applies when Observation.component is used. I.e., if Observation.component.value[x] is missed, then Observation.component.dataAbsentReason SHALL be present with the reason.