> ## Documentation Index > Fetch the complete documentation index at: https://docs.metriport.com/llms.txt > Use this file to discover all available pages before exploring further. # Observation > Measurements and simple assertions made about a patient, device or other subject. ## Properties | Name | Required | Type | Description | | ------------------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------- | | identifier | No | [Identifier](/medical-api/fhir/data-types/identifier)\[] | Business Identifier for observation | | basedOn | No | Reference\<[CarePlan](/medical-api/fhir/resources/careplan) / [DeviceRequest](/medical-api/fhir/resources/devicerequest) / [ImmunizationRecommendation](/medical-api/fhir/resources/immunizationrecommendation) / [MedicationRequest](/medical-api/fhir/resources/medicationrequest) / [NutritionOrder](/medical-api/fhir/resources/nutritionorder) / [ServiceRequest](/medical-api/fhir/resources/servicerequest)>\[] | Fulfills plan, proposal or order | | partOf | No | Reference\<[MedicationAdministration](/medical-api/fhir/resources/medicationadministration) / [MedicationDispense](/medical-api/fhir/resources/medicationdispense) / [MedicationStatement](/medical-api/fhir/resources/medicationstatement) / [Procedure](/medical-api/fhir/resources/procedure) / [Immunization](/medical-api/fhir/resources/immunization) / [ImagingStudy](/medical-api/fhir/resources/imagingstudy)>\[] | Part of referenced event | | status | Yes | code | registered / preliminary / final / amended + | | category | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | Classification of type of observation | | code | Yes | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Type of observation (code / type) | | subject | No | Reference\<[Patient](/medical-api/fhir/resources/patient) / [Group](/medical-api/fhir/resources/group) / [Device](/medical-api/fhir/resources/device) / [Location](/medical-api/fhir/resources/location)> | Who and/or what the observation is about | | focus | No | Reference\\[] | What the observation is about, when it is not about the subject of record | | encounter | No | Reference\<[Encounter](/medical-api/fhir/resources/encounter)> | Healthcare event during which this observation is made | | effective\[x] | No | dateTime, [Period](/medical-api/fhir/data-types/period), [Timing](/medical-api/fhir/data-types/timing), instant | Clinically relevant time/time-period for observation | | issued | No | instant | Date/Time this version was made available | | performer | No | Reference\<[Practitioner](/medical-api/fhir/resources/practitioner) / [PractitionerRole](/medical-api/fhir/resources/practitionerrole) / [Organization](/medical-api/fhir/resources/organization) / [CareTeam](/medical-api/fhir/resources/careteam) / [Patient](/medical-api/fhir/resources/patient) / [RelatedPerson](/medical-api/fhir/resources/relatedperson)>\[] | Who is responsible for the observation | | value\[x] | No | [Quantity](/medical-api/fhir/data-types/quantity), [CodeableConcept](/medical-api/fhir/data-types/codeableconcept), string, boolean, integer, [Range](/medical-api/fhir/data-types/range), [Ratio](/medical-api/fhir/data-types/ratio), [SampledData](/medical-api/fhir/data-types/sampleddata), time, dateTime, [Period](/medical-api/fhir/data-types/period) | Actual result | | dataAbsentReason | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Why the result is missing | | interpretation | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | High, low, normal, etc. | | note | No | [Annotation](/medical-api/fhir/data-types/annotation)\[] | Comments about the observation | | bodySite | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Observed body part | | method | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | How it was done | | specimen | No | Reference\<[Specimen](/medical-api/fhir/resources/specimen)> | Specimen used for this observation | | device | No | Reference\<[Device](/medical-api/fhir/resources/device) / [DeviceMetric](/medical-api/fhir/resources/devicemetric)> | (Measurement) Device | | referenceRange | No | ObservationReferenceRange | Provides guide for interpretation | | - id | No | string | Unique id for inter-element referencing | | - extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations | | - modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored even if unrecognized | | - low | No | [Quantity](/medical-api/fhir/data-types/quantity) | Low Range, if relevant | | - high | No | [Quantity](/medical-api/fhir/data-types/quantity) | High Range, if relevant | | - type | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Reference range qualifier | | - appliesTo | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | Reference range population | | - age | No | [Range](/medical-api/fhir/data-types/range) | Applicable age range, if relevant | | - text | No | string | Text based reference range in an observation | | hasMember | No | Reference\<[Observation](/medical-api/fhir/resources/observation) / [QuestionnaireResponse](/medical-api/fhir/resources/questionnaireresponse) / [MolecularSequence](/medical-api/fhir/resources/molecularsequence)>\[] | Related resource that belongs to the Observation group | | derivedFrom | No | Reference\<[DocumentReference](/medical-api/fhir/resources/documentreference) / [ImagingStudy](/medical-api/fhir/resources/imagingstudy) / [Media](/medical-api/fhir/resources/media) / [QuestionnaireResponse](/medical-api/fhir/resources/questionnaireresponse) / [Observation](/medical-api/fhir/resources/observation) / [MolecularSequence](/medical-api/fhir/resources/molecularsequence)>\[] | Related measurements the observation is made from | | component | No | ObservationComponent | Component results | | - id | No | string | Unique id for inter-element referencing | | - extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations | | - modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored even if unrecognized | | - code | Yes | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Type of component observation (code / type) | | - value\[x] | No | [Quantity](/medical-api/fhir/data-types/quantity), [CodeableConcept](/medical-api/fhir/data-types/codeableconcept), string, boolean, integer, [Range](/medical-api/fhir/data-types/range), [Ratio](/medical-api/fhir/data-types/ratio), [SampledData](/medical-api/fhir/data-types/sampleddata), time, dateTime, [Period](/medical-api/fhir/data-types/period) | Actual component result | | - dataAbsentReason | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Why the component result is missing | | - interpretation | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | High, low, normal, etc. | | - referenceRange | No | \[] | Provides guide for interpretation of component result | ## Search Parameters | Name | Type | Description | Expression | | ----------------------------- | --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------- | | code | token | The code of the observation type | Observation.code | | date | date | Obtained date/time. If the obtained element is a period, a date that falls in the period | Observation.effective | | identifier | token | The unique id for a particular observation | Observation.identifier | | patient | reference | The subject that the observation is about (if patient) | Observation.subject | | encounter | reference | Encounter related to the observation | Observation.encounter | | based-on | reference | Reference to the service request. | Observation.basedOn | | category | token | The classification of the type of observation | Observation.category | | combo-code | token | The code of the observation type or component type | Observation.code | | combo-data-absent-reason | token | The reason why the expected value in the element Observation.value\[x] or Observation.component.value\[x] is missing. | Observation.dataAbsentReason | | combo-value-concept | token | The value or component value of the observation, if the value is a CodeableConcept | Observation.value | | combo-value-quantity | quantity | The value or component value of the observation, if the value is a Quantity, or a SampledData (just search on the bounds of the values in sampled data) | Observation.value | | component-code | token | The component code of the observation type | Observation.component.code | | component-data-absent-reason | token | The reason why the expected value in the element Observation.component.value\[x] is missing. | Observation.component.dataAbsentReason | | component-value-concept | token | The value of the component observation, if the value is a CodeableConcept | Observation.component.value | | component-value-quantity | quantity | The value of the component observation, if the value is a Quantity, or a SampledData (just search on the bounds of the values in sampled data) | Observation.component.value | | data-absent-reason | token | The reason why the expected value in the element Observation.value\[x] is missing. | Observation.dataAbsentReason | | derived-from | reference | Related measurements the observation is made from | Observation.derivedFrom | | device | reference | The Device that generated the observation data. | Observation.device | | focus | reference | The focus of an observation when the focus is not the patient of record. | Observation.focus | | has-member | reference | Related resource that belongs to the Observation group | Observation.hasMember | | method | token | The method used for the observation | Observation.method | | part-of | reference | Part of referenced event | Observation.partOf | | performer | reference | Who performed the observation | Observation.performer | | specimen | reference | Specimen used for this observation | Observation.specimen | | status | token | The status of the observation | Observation.status | | subject | reference | The subject that the observation is about | Observation.subject | | value-concept | token | The value of the observation, if the value is a CodeableConcept | Observation.value | | value-date | date | The value of the observation, if the value is a date or period of time | Observation.value | | value-quantity | quantity | The value of the observation, if the value is a Quantity, or a SampledData (just search on the bounds of the values in sampled data) | Observation.value | | value-string | string | The value of the observation, if the value is a string, and also searches in CodeableConcept.text | Observation.value | | code-value-concept | composite | Code and coded value parameter pair | | | code-value-date | composite | Code and date/time value parameter pair | | | code-value-quantity | composite | Code and quantity value parameter pair | | | code-value-string | composite | Code and string value parameter pair | | | combo-code-value-concept | composite | Code and coded value parameter pair, including in components | Observation.component | | combo-code-value-quantity | composite | Code and quantity value parameter pair, including in components | Observation.component | | component-code-value-concept | composite | Component code and component coded value parameter pair | Observation.component | | component-code-value-quantity | composite | Component code and component quantity value parameter pair | Observation.component | ## Inherited Properties | Name | Required | Type | Description | | ----------------- | -------- | ------------------------------------------------------ | ------------------------------------------------------ | | id | No | string | Logical id of this artifact | | meta | No | [Meta](/medical-api/fhir/data-types/meta) | Metadata about the resource | | implicitRules | No | uri | A set of rules under which this content was created | | language | No | code | Language of the resource content | | text | No | [Narrative](/medical-api/fhir/data-types/narrative) | Text summary of the resource, for human interpretation | | contained | No | Resource\[] | Contained, inline Resources | | extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations | | modifierExtension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored | To view the FHIR specification for this resource, see [Observation](https://www.hl7.org/fhir/StructureDefinition/Observation).