The type of exposure/contact is contained in Observation.code (environmental, activity, event, location, person, animal, etc.). This value could come from one of the following value sets:

• Exposure Setting (COVID-19)
• Exposure Location or may be selected from another suitable value set (e.g.: Social History Type)

If the exposure/contact is an entity (person, animal, location) then it is represented in Observation.focus which is a reference to a Patient, RelatedPerson, Location, Group, etc.. (An animal would be represented by a RelatedPerson that contains the Extension Practitioner Animal Species). This focus contains either:

• the patient’s contact with an entity (person, animal, or substance) or presence at a location where exposure to an agent could have occurred (aquisition exposure)
• the patient’s contact with an entity (person, animal, or substance) or presence at a location where transmission from the patient could have occurred (transmission exposure)

Free text information about the exposure/contact can be recorded in Observation.valueString and the date or period of exposure is held in Observation.effective[x]. If an address where the exposure/contact took place is known then it can be contained in the address-extension.

The possible agent of concern in the exposure is recorded in Observation.component.

The following are some exposures that might be captured in this profile:

• Environmental exposures
  • Living facilities
  • Work facilities
  • School facilities
• Contact exposures
  • Person
  • Animal
• Event Exposures
  • Sporting event
  • Rally
  • Wedding
  • Activity

• Differential Table
• Key Elements Table
• Snapshot Table
• Statistics/References
• All

This structure is derived from Observation

Name	Flags	Card.	Type	Description & Constraints
Observation		0..*	Observation	US Public Health Exposure Contact Information
us-ph-address-extension	S	0..1	Address	Exposure/contact address URL: http://hl7.org/fhir/us/ecr/StructureDefinition/us-ph-address-extension
category	S	1..1	CodeableConcept	Use AEXPOS for aquisition exposure, use TEXPOS for transmission exposure, or use EXPOS if the type of exposure is unknown Binding: ActClassExposure (required): ActClassExposure
code	S	1..1	CodeableConcept	The type of exposure/contact (environmental, activity, event, location, person, animal, etc.).
subject	S	1..1	Reference(US Public Health Patient)	Who and/or what the observation is about
focus	S	0..*	Reference(US Public Health Patient | RelatedPerson | Group | US Core Location Profile)	Contains either the patient's contact with an entity (person, animal, or substance) or presence at a location where exposure to an agent could have occurred or the patient's contact with an entity (person, animal, or substance) or presence at a location where transmission from the patient could have occurred
effective[x]	S	0..1	dateTime, Period, Timing, instant	Time or period the contact/exposure occurred.
value[x]	S	0..1		Specific exposure/contact
valueCodeableConcept			CodeableConcept
valueString			string
component	S	0..*	BackboneElement	Possible agent of concern in the exposure
code	S	1..1	CodeableConcept	ExposureAgent Required Pattern: At least the following
coding		1..*	Coding	Code defined by a terminology system Fixed Value: (complex)
system		1..1	uri	Identity of the terminology system Fixed Value: http://terminology.hl7.org/CodeSystem/v3-ParticipationType
code		1..1	code	Symbol in syntax defined by the system Fixed Value: EXPAGNT
value[x]	S	1..1		Possible agent of concern in the exposure
valueCodeableConcept			CodeableConcept
valueString			string
Documentation for this format

Terminology Bindings (Differential)

Path	Conformance	ValueSet
Observation.category	required	ActClassExposure

Name	Flags	Card.	Type	Description & Constraints
Observation	C	0..*	Observation	US Public Health Exposure Contact Information
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
us-ph-address-extension	S	0..1	Address	Exposure/contact address URL: http://hl7.org/fhir/us/ecr/StructureDefinition/us-ph-address-extension
modifierExtension	?!	0..*	Extension	Extensions that cannot be ignored
status	?!Σ	1..1	code	registered | preliminary | final | amended + Binding: ObservationStatus (required): Codes providing the status of an observation.
category	S	1..1	CodeableConcept	Use AEXPOS for aquisition exposure, use TEXPOS for transmission exposure, or use EXPOS if the type of exposure is unknown Binding: ActClassExposure (required): ActClassExposure
code	SΣ	1..1	CodeableConcept	The type of exposure/contact (environmental, activity, event, location, person, animal, etc.). Binding: LOINCCodes (example): Codes identifying names of simple observations.
subject	SΣ	1..1	Reference(US Public Health Patient)	Who and/or what the observation is about
focus	SΣ	0..*	Reference(US Public Health Patient | RelatedPerson | Group | US Core Location Profile)	Contains either the patient's contact with an entity (person, animal, or substance) or presence at a location where exposure to an agent could have occurred or the patient's contact with an entity (person, animal, or substance) or presence at a location where transmission from the patient could have occurred
effective[x]	SΣ	0..1		Time or period the contact/exposure occurred.
effectiveDateTime			dateTime
effectivePeriod			Period
effectiveTiming			Timing
effectiveInstant			instant
value[x]	SΣC	0..1		Specific exposure/contact
valueCodeableConcept			CodeableConcept
valueString			string
component	SΣ	0..*	BackboneElement	Possible agent of concern in the exposure
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
code	SΣ	1..1	CodeableConcept	ExposureAgent Binding: LOINCCodes (example): Codes identifying names of simple observations. Required Pattern: At least the following
coding		1..*	Coding	Code defined by a terminology system Fixed Value: (complex)
system		1..1	uri	Identity of the terminology system Fixed Value: http://terminology.hl7.org/CodeSystem/v3-ParticipationType
code		1..1	code	Symbol in syntax defined by the system Fixed Value: EXPAGNT
value[x]	SΣ	1..1		Possible agent of concern in the exposure
valueCodeableConcept			CodeableConcept
valueString			string
Documentation for this format

Terminology Bindings

Path	Conformance	ValueSet / Code
Observation.status	required	ObservationStatus
Observation.category	required	ActClassExposure
Observation.code	example	LOINCCodes (a valid code from LOINC)
Observation.component.code	example	Pattern: EXPAGNT

Constraints

Id	Grade	Path(s)	Details	Requirements
dom-2	error	Observation	If the resource is contained in another resource, it SHALL NOT contain nested Resources : contained.contained.empty()
dom-3	error	Observation	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	error	Observation	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	error	Observation	If a resource is contained in another resource, it SHALL NOT have a security label : contained.meta.security.empty()
dom-6	best practice	Observation	A resource should have narrative for robust management : text.`div`.exists()
ele-1	error	**ALL** elements	All FHIR elements must have a @value or children : hasValue() or (children().count() > id.count())
ext-1	error	**ALL** extensions	Must have either extensions or value[x], not both : extension.exists() != value.exists()
obs-6	error	Observation	dataAbsentReason SHALL only be present if Observation.value[x] is not present : dataAbsentReason.empty() or value.empty()
obs-7	error	Observation	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()

Name	Flags	Card.	Type	Description & Constraints
Observation	C	0..*	Observation	US Public Health Exposure Contact Information
id	Σ	0..1	id	Logical id of this artifact
meta	Σ	0..1	Meta	Metadata about the resource
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
language		0..1	code	Language of the resource content Binding: CommonLanguages (preferred): A human language. Additional Bindings Purpose AllLanguages Max Binding
text		0..1	Narrative	Text summary of the resource, for human interpretation
contained		0..*	Resource	Contained, inline Resources
us-ph-address-extension	S	0..1	Address	Exposure/contact address URL: http://hl7.org/fhir/us/ecr/StructureDefinition/us-ph-address-extension
modifierExtension	?!	0..*	Extension	Extensions that cannot be ignored
identifier	Σ	0..*	Identifier	Business Identifier for observation
basedOn	Σ	0..*	Reference(CarePlan | DeviceRequest | ImmunizationRecommendation | MedicationRequest | NutritionOrder | ServiceRequest)	Fulfills plan, proposal or order
partOf	Σ	0..*	Reference(MedicationAdministration | MedicationDispense | MedicationStatement | Procedure | Immunization | ImagingStudy)	Part of referenced event
status	?!Σ	1..1	code	registered | preliminary | final | amended + Binding: ObservationStatus (required): Codes providing the status of an observation.
category	S	1..1	CodeableConcept	Use AEXPOS for aquisition exposure, use TEXPOS for transmission exposure, or use EXPOS if the type of exposure is unknown Binding: ActClassExposure (required): ActClassExposure
code	SΣ	1..1	CodeableConcept	The type of exposure/contact (environmental, activity, event, location, person, animal, etc.). Binding: LOINCCodes (example): Codes identifying names of simple observations.
subject	SΣ	1..1	Reference(US Public Health Patient)	Who and/or what the observation is about
focus	SΣ	0..*	Reference(US Public Health Patient | RelatedPerson | Group | US Core Location Profile)	Contains either the patient's contact with an entity (person, animal, or substance) or presence at a location where exposure to an agent could have occurred or the patient's contact with an entity (person, animal, or substance) or presence at a location where transmission from the patient could have occurred
encounter	Σ	0..1	Reference(Encounter)	Healthcare event during which this observation is made
effective[x]	SΣ	0..1		Time or period the contact/exposure occurred.
effectiveDateTime			dateTime
effectivePeriod			Period
effectiveTiming			Timing
effectiveInstant			instant
issued	Σ	0..1	instant	Date/Time this version was made available
performer	Σ	0..*	Reference(Practitioner | PractitionerRole | Organization | CareTeam | Patient | RelatedPerson)	Who is responsible for the observation
value[x]	SΣC	0..1		Specific exposure/contact
valueCodeableConcept			CodeableConcept
valueString			string
dataAbsentReason	C	0..1	CodeableConcept	Why the result is missing Binding: DataAbsentReason (extensible): Codes specifying why the result (Observation.value[x]) is missing.
interpretation		0..*	CodeableConcept	High, low, normal, etc. Binding: ObservationInterpretationCodes (extensible): Codes identifying interpretations of observations.
note		0..*	Annotation	Comments about the observation
bodySite		0..1	CodeableConcept	Observed body part Binding: SNOMEDCTBodyStructures (example): Codes describing anatomical locations. May include laterality.
method		0..1	CodeableConcept	How it was done Binding: ObservationMethods (example): Methods for simple observations.
specimen		0..1	Reference(Specimen)	Specimen used for this observation
device		0..1	Reference(Device | DeviceMetric)	(Measurement) Device
referenceRange	C	0..*	BackboneElement	Provides guide for interpretation
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
low	C	0..1	SimpleQuantity	Low Range, if relevant
high	C	0..1	SimpleQuantity	High Range, if relevant
type		0..1	CodeableConcept	Reference range qualifier Binding: ObservationReferenceRangeMeaningCodes (preferred): Code for the meaning of a reference range.
appliesTo		0..*	CodeableConcept	Reference range population Binding: ObservationReferenceRangeAppliesToCodes (example): Codes identifying the population the reference range applies to.
age		0..1	Range	Applicable age range, if relevant
text		0..1	string	Text based reference range in an observation
hasMember	Σ	0..*	Reference(Observation | QuestionnaireResponse | MolecularSequence)	Related resource that belongs to the Observation group
derivedFrom	Σ	0..*	Reference(DocumentReference | ImagingStudy | Media | QuestionnaireResponse | Observation | MolecularSequence)	Related measurements the observation is made from
component	SΣ	0..*	BackboneElement	Possible agent of concern in the exposure
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
code	SΣ	1..1	CodeableConcept	ExposureAgent Binding: LOINCCodes (example): Codes identifying names of simple observations. Required Pattern: At least the following
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
coding		1..*	Coding	Code defined by a terminology system Fixed Value: (complex)
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
system		1..1	uri	Identity of the terminology system Fixed Value: http://terminology.hl7.org/CodeSystem/v3-ParticipationType
version		0..1	string	Version of the system - if relevant
code		1..1	code	Symbol in syntax defined by the system Fixed Value: EXPAGNT
display		0..1	string	Representation defined by the system
userSelected		0..1	boolean	If this coding was chosen directly by the user
text		0..1	string	Plain text representation of the concept
value[x]	SΣ	1..1		Possible agent of concern in the exposure
valueCodeableConcept			CodeableConcept
valueString			string
dataAbsentReason	C	0..1	CodeableConcept	Why the component result is missing Binding: DataAbsentReason (extensible): Codes specifying why the result (Observation.value[x]) is missing.
interpretation		0..*	CodeableConcept	High, low, normal, etc. Binding: ObservationInterpretationCodes (extensible): Codes identifying interpretations of observations.
referenceRange		0..*	See referenceRange (Observation)	Provides guide for interpretation of component result
Documentation for this format

Terminology Bindings

Path	Conformance	ValueSet / Code
Observation.language	preferred	CommonLanguages Additional Bindings Purpose AllLanguages Max Binding
Observation.status	required	ObservationStatus
Observation.category	required	ActClassExposure
Observation.code	example	LOINCCodes (a valid code from LOINC)
Observation.dataAbsentReason	extensible	DataAbsentReason
Observation.interpretation	extensible	ObservationInterpretationCodes
Observation.bodySite	example	SNOMEDCTBodyStructures
Observation.method	example	ObservationMethods
Observation.referenceRange.type	preferred	ObservationReferenceRangeMeaningCodes
Observation.referenceRange.appliesTo	example	ObservationReferenceRangeAppliesToCodes
Observation.component.code	example	Pattern: EXPAGNT
Observation.component.dataAbsentReason	extensible	DataAbsentReason
Observation.component.interpretation	extensible	ObservationInterpretationCodes

Constraints

Id	Grade	Path(s)	Details	Requirements
dom-2	error	Observation	If the resource is contained in another resource, it SHALL NOT contain nested Resources : contained.contained.empty()
dom-3	error	Observation	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	error	Observation	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	error	Observation	If a resource is contained in another resource, it SHALL NOT have a security label : contained.meta.security.empty()
dom-6	best practice	Observation	A resource should have narrative for robust management : text.`div`.exists()
ele-1	error	**ALL** elements	All FHIR elements must have a @value or children : hasValue() or (children().count() > id.count())
ext-1	error	**ALL** extensions	Must have either extensions or value[x], not both : extension.exists() != value.exists()
obs-3	error	Observation.referenceRange	Must have at least a low or a high or text : low.exists() or high.exists() or text.exists()
obs-6	error	Observation	dataAbsentReason SHALL only be present if Observation.value[x] is not present : dataAbsentReason.empty() or value.empty()
obs-7	error	Observation	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()

Differential View

This structure is derived from Observation

Name	Flags	Card.	Type	Description & Constraints
Observation		0..*	Observation	US Public Health Exposure Contact Information
us-ph-address-extension	S	0..1	Address	Exposure/contact address URL: http://hl7.org/fhir/us/ecr/StructureDefinition/us-ph-address-extension
category	S	1..1	CodeableConcept	Use AEXPOS for aquisition exposure, use TEXPOS for transmission exposure, or use EXPOS if the type of exposure is unknown Binding: ActClassExposure (required): ActClassExposure
code	S	1..1	CodeableConcept	The type of exposure/contact (environmental, activity, event, location, person, animal, etc.).
subject	S	1..1	Reference(US Public Health Patient)	Who and/or what the observation is about
focus	S	0..*	Reference(US Public Health Patient | RelatedPerson | Group | US Core Location Profile)	Contains either the patient's contact with an entity (person, animal, or substance) or presence at a location where exposure to an agent could have occurred or the patient's contact with an entity (person, animal, or substance) or presence at a location where transmission from the patient could have occurred
effective[x]	S	0..1	dateTime, Period, Timing, instant	Time or period the contact/exposure occurred.
value[x]	S	0..1		Specific exposure/contact
valueCodeableConcept			CodeableConcept
valueString			string
component	S	0..*	BackboneElement	Possible agent of concern in the exposure
code	S	1..1	CodeableConcept	ExposureAgent Required Pattern: At least the following
coding		1..*	Coding	Code defined by a terminology system Fixed Value: (complex)
system		1..1	uri	Identity of the terminology system Fixed Value: http://terminology.hl7.org/CodeSystem/v3-ParticipationType
code		1..1	code	Symbol in syntax defined by the system Fixed Value: EXPAGNT
value[x]	S	1..1		Possible agent of concern in the exposure
valueCodeableConcept			CodeableConcept
valueString			string
Documentation for this format

Terminology Bindings (Differential)

Path	Conformance	ValueSet
Observation.category	required	ActClassExposure

Key Elements View

Name	Flags	Card.	Type	Description & Constraints
Observation	C	0..*	Observation	US Public Health Exposure Contact Information
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
us-ph-address-extension	S	0..1	Address	Exposure/contact address URL: http://hl7.org/fhir/us/ecr/StructureDefinition/us-ph-address-extension
modifierExtension	?!	0..*	Extension	Extensions that cannot be ignored
status	?!Σ	1..1	code	registered | preliminary | final | amended + Binding: ObservationStatus (required): Codes providing the status of an observation.
category	S	1..1	CodeableConcept	Use AEXPOS for aquisition exposure, use TEXPOS for transmission exposure, or use EXPOS if the type of exposure is unknown Binding: ActClassExposure (required): ActClassExposure
code	SΣ	1..1	CodeableConcept	The type of exposure/contact (environmental, activity, event, location, person, animal, etc.). Binding: LOINCCodes (example): Codes identifying names of simple observations.
subject	SΣ	1..1	Reference(US Public Health Patient)	Who and/or what the observation is about
focus	SΣ	0..*	Reference(US Public Health Patient | RelatedPerson | Group | US Core Location Profile)	Contains either the patient's contact with an entity (person, animal, or substance) or presence at a location where exposure to an agent could have occurred or the patient's contact with an entity (person, animal, or substance) or presence at a location where transmission from the patient could have occurred
effective[x]	SΣ	0..1		Time or period the contact/exposure occurred.
effectiveDateTime			dateTime
effectivePeriod			Period
effectiveTiming			Timing
effectiveInstant			instant
value[x]	SΣC	0..1		Specific exposure/contact
valueCodeableConcept			CodeableConcept
valueString			string
component	SΣ	0..*	BackboneElement	Possible agent of concern in the exposure
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
code	SΣ	1..1	CodeableConcept	ExposureAgent Binding: LOINCCodes (example): Codes identifying names of simple observations. Required Pattern: At least the following
coding		1..*	Coding	Code defined by a terminology system Fixed Value: (complex)
system		1..1	uri	Identity of the terminology system Fixed Value: http://terminology.hl7.org/CodeSystem/v3-ParticipationType
code		1..1	code	Symbol in syntax defined by the system Fixed Value: EXPAGNT
value[x]	SΣ	1..1		Possible agent of concern in the exposure
valueCodeableConcept			CodeableConcept
valueString			string
Documentation for this format

Terminology Bindings

Path	Conformance	ValueSet / Code
Observation.status	required	ObservationStatus
Observation.category	required	ActClassExposure
Observation.code	example	LOINCCodes (a valid code from LOINC)
Observation.component.code	example	Pattern: EXPAGNT

Constraints

Id	Grade	Path(s)	Details	Requirements
dom-2	error	Observation	If the resource is contained in another resource, it SHALL NOT contain nested Resources : contained.contained.empty()
dom-3	error	Observation	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	error	Observation	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	error	Observation	If a resource is contained in another resource, it SHALL NOT have a security label : contained.meta.security.empty()
dom-6	best practice	Observation	A resource should have narrative for robust management : text.`div`.exists()
ele-1	error	**ALL** elements	All FHIR elements must have a @value or children : hasValue() or (children().count() > id.count())
ext-1	error	**ALL** extensions	Must have either extensions or value[x], not both : extension.exists() != value.exists()
obs-6	error	Observation	dataAbsentReason SHALL only be present if Observation.value[x] is not present : dataAbsentReason.empty() or value.empty()
obs-7	error	Observation	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()

Snapshot View

Name	Flags	Card.	Type	Description & Constraints
Observation	C	0..*	Observation	US Public Health Exposure Contact Information
id	Σ	0..1	id	Logical id of this artifact
meta	Σ	0..1	Meta	Metadata about the resource
implicitRules	?!Σ	0..1	uri	A set of rules under which this content was created
language		0..1	code	Language of the resource content Binding: CommonLanguages (preferred): A human language. Additional Bindings Purpose AllLanguages Max Binding
text		0..1	Narrative	Text summary of the resource, for human interpretation
contained		0..*	Resource	Contained, inline Resources
us-ph-address-extension	S	0..1	Address	Exposure/contact address URL: http://hl7.org/fhir/us/ecr/StructureDefinition/us-ph-address-extension
modifierExtension	?!	0..*	Extension	Extensions that cannot be ignored
identifier	Σ	0..*	Identifier	Business Identifier for observation
basedOn	Σ	0..*	Reference(CarePlan | DeviceRequest | ImmunizationRecommendation | MedicationRequest | NutritionOrder | ServiceRequest)	Fulfills plan, proposal or order
partOf	Σ	0..*	Reference(MedicationAdministration | MedicationDispense | MedicationStatement | Procedure | Immunization | ImagingStudy)	Part of referenced event
status	?!Σ	1..1	code	registered | preliminary | final | amended + Binding: ObservationStatus (required): Codes providing the status of an observation.
category	S	1..1	CodeableConcept	Use AEXPOS for aquisition exposure, use TEXPOS for transmission exposure, or use EXPOS if the type of exposure is unknown Binding: ActClassExposure (required): ActClassExposure
code	SΣ	1..1	CodeableConcept	The type of exposure/contact (environmental, activity, event, location, person, animal, etc.). Binding: LOINCCodes (example): Codes identifying names of simple observations.
subject	SΣ	1..1	Reference(US Public Health Patient)	Who and/or what the observation is about
focus	SΣ	0..*	Reference(US Public Health Patient | RelatedPerson | Group | US Core Location Profile)	Contains either the patient's contact with an entity (person, animal, or substance) or presence at a location where exposure to an agent could have occurred or the patient's contact with an entity (person, animal, or substance) or presence at a location where transmission from the patient could have occurred
encounter	Σ	0..1	Reference(Encounter)	Healthcare event during which this observation is made
effective[x]	SΣ	0..1		Time or period the contact/exposure occurred.
effectiveDateTime			dateTime
effectivePeriod			Period
effectiveTiming			Timing
effectiveInstant			instant
issued	Σ	0..1	instant	Date/Time this version was made available
performer	Σ	0..*	Reference(Practitioner | PractitionerRole | Organization | CareTeam | Patient | RelatedPerson)	Who is responsible for the observation
value[x]	SΣC	0..1		Specific exposure/contact
valueCodeableConcept			CodeableConcept
valueString			string
dataAbsentReason	C	0..1	CodeableConcept	Why the result is missing Binding: DataAbsentReason (extensible): Codes specifying why the result (Observation.value[x]) is missing.
interpretation		0..*	CodeableConcept	High, low, normal, etc. Binding: ObservationInterpretationCodes (extensible): Codes identifying interpretations of observations.
note		0..*	Annotation	Comments about the observation
bodySite		0..1	CodeableConcept	Observed body part Binding: SNOMEDCTBodyStructures (example): Codes describing anatomical locations. May include laterality.
method		0..1	CodeableConcept	How it was done Binding: ObservationMethods (example): Methods for simple observations.
specimen		0..1	Reference(Specimen)	Specimen used for this observation
device		0..1	Reference(Device | DeviceMetric)	(Measurement) Device
referenceRange	C	0..*	BackboneElement	Provides guide for interpretation
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
low	C	0..1	SimpleQuantity	Low Range, if relevant
high	C	0..1	SimpleQuantity	High Range, if relevant
type		0..1	CodeableConcept	Reference range qualifier Binding: ObservationReferenceRangeMeaningCodes (preferred): Code for the meaning of a reference range.
appliesTo		0..*	CodeableConcept	Reference range population Binding: ObservationReferenceRangeAppliesToCodes (example): Codes identifying the population the reference range applies to.
age		0..1	Range	Applicable age range, if relevant
text		0..1	string	Text based reference range in an observation
hasMember	Σ	0..*	Reference(Observation | QuestionnaireResponse | MolecularSequence)	Related resource that belongs to the Observation group
derivedFrom	Σ	0..*	Reference(DocumentReference | ImagingStudy | Media | QuestionnaireResponse | Observation | MolecularSequence)	Related measurements the observation is made from
component	SΣ	0..*	BackboneElement	Possible agent of concern in the exposure
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
modifierExtension	?!Σ	0..*	Extension	Extensions that cannot be ignored even if unrecognized
code	SΣ	1..1	CodeableConcept	ExposureAgent Binding: LOINCCodes (example): Codes identifying names of simple observations. Required Pattern: At least the following
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
coding		1..*	Coding	Code defined by a terminology system Fixed Value: (complex)
id		0..1	string	Unique id for inter-element referencing
extension		0..*	Extension	Additional content defined by implementations
system		1..1	uri	Identity of the terminology system Fixed Value: http://terminology.hl7.org/CodeSystem/v3-ParticipationType
version		0..1	string	Version of the system - if relevant
code		1..1	code	Symbol in syntax defined by the system Fixed Value: EXPAGNT
display		0..1	string	Representation defined by the system
userSelected		0..1	boolean	If this coding was chosen directly by the user
text		0..1	string	Plain text representation of the concept
value[x]	SΣ	1..1		Possible agent of concern in the exposure
valueCodeableConcept			CodeableConcept
valueString			string
dataAbsentReason	C	0..1	CodeableConcept	Why the component result is missing Binding: DataAbsentReason (extensible): Codes specifying why the result (Observation.value[x]) is missing.
interpretation		0..*	CodeableConcept	High, low, normal, etc. Binding: ObservationInterpretationCodes (extensible): Codes identifying interpretations of observations.
referenceRange		0..*	See referenceRange (Observation)	Provides guide for interpretation of component result
Documentation for this format

Terminology Bindings

Path	Conformance	ValueSet / Code
Observation.language	preferred	CommonLanguages Additional Bindings Purpose AllLanguages Max Binding
Observation.status	required	ObservationStatus
Observation.category	required	ActClassExposure
Observation.code	example	LOINCCodes (a valid code from LOINC)
Observation.dataAbsentReason	extensible	DataAbsentReason
Observation.interpretation	extensible	ObservationInterpretationCodes
Observation.bodySite	example	SNOMEDCTBodyStructures
Observation.method	example	ObservationMethods
Observation.referenceRange.type	preferred	ObservationReferenceRangeMeaningCodes
Observation.referenceRange.appliesTo	example	ObservationReferenceRangeAppliesToCodes
Observation.component.code	example	Pattern: EXPAGNT
Observation.component.dataAbsentReason	extensible	DataAbsentReason
Observation.component.interpretation	extensible	ObservationInterpretationCodes

Constraints

Id	Grade	Path(s)	Details	Requirements
dom-2	error	Observation	If the resource is contained in another resource, it SHALL NOT contain nested Resources : contained.contained.empty()
dom-3	error	Observation	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	error	Observation	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	error	Observation	If a resource is contained in another resource, it SHALL NOT have a security label : contained.meta.security.empty()
dom-6	best practice	Observation	A resource should have narrative for robust management : text.`div`.exists()
ele-1	error	**ALL** elements	All FHIR elements must have a @value or children : hasValue() or (children().count() > id.count())
ext-1	error	**ALL** extensions	Must have either extensions or value[x], not both : extension.exists() != value.exists()
obs-3	error	Observation.referenceRange	Must have at least a low or a high or text : low.exists() or high.exists() or text.exists()
obs-6	error	Observation	dataAbsentReason SHALL only be present if Observation.value[x] is not present : dataAbsentReason.empty() or value.empty()
obs-7	error	Observation	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()

This structure is derived from Observation

Summary

Mandatory: 3 elements (1 nested mandatory element)
Must-Support: 10 elements

Structures

This structure refers to these other structures:

• US Public Health Patient (http://hl7.org/fhir/us/ecr/StructureDefinition/us-ph-patient)
• US Core Location Profile (http://hl7.org/fhir/us/core/StructureDefinition/us-core-location)

Extensions

This structure refers to these extensions:

• http://hl7.org/fhir/us/ecr/StructureDefinition/us-ph-address-extension