> ## 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. # ObservationDefinition > Set of definitional characteristics for a kind of observation or measurement produced or consumed by an orderable health care service. ## Properties | Name | Required | Type | Description | | ---------------------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- | | publisher | No | Reference\<[Practitioner](/medical-api/fhir/resources/practitioner) / [PractitionerRole](/medical-api/fhir/resources/practitionerrole) / [Organization](/medical-api/fhir/resources/organization)> | The name of the individual or organization that published the ObservationDefinition | | category | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | Category of observation | | code | Yes | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Type of observation (code / type) | | identifier | No | [Identifier](/medical-api/fhir/data-types/identifier)\[] | Business identifier for this ObservationDefinition instance | | permittedDataType | No | code\[] | Quantity / CodeableConcept / string / boolean / integer / Range / Ratio / SampledData / time / dateTime / Period | | multipleResultsAllowed | No | boolean | Multiple results allowed | | method | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Method used to produce the observation | | preferredReportName | No | string | Preferred report name | | quantitativeDetails | No | ObservationDefinitionQuantitativeDetails | Characteristics of quantitative 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 | | - customaryUnit | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Customary unit for quantitative results | | - unit | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | SI unit for quantitative results | | - conversionFactor | No | decimal | SI to Customary unit conversion factor | | - decimalPrecision | No | integer | Decimal precision of observation quantitative results | | qualifiedInterval | No | ObservationDefinitionQualifiedInterval | Qualified range for continuous and ordinal observation 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 | | - category | No | code | reference / critical / absolute | | - range | No | [Range](/medical-api/fhir/data-types/range) | The interval itself, for continuous or ordinal observations | | - context | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept) | Range context qualifier | | - appliesTo | No | [CodeableConcept](/medical-api/fhir/data-types/codeableconcept)\[] | Targetted population of the range | | - gender | No | code | male / female / other / unknown | | - age | No | [Range](/medical-api/fhir/data-types/range) | Applicable age range, if relevant | | - gestationalAge | No | [Range](/medical-api/fhir/data-types/range) | Applicable gestational age range, if relevant | | - condition | No | string | Condition associated with the reference range | | validCodedValueSet | No | Reference\<[ValueSet](/medical-api/fhir/resources/valueset)> | Value set of valid coded values for the observations conforming to this ObservationDefinition | | normalCodedValueSet | No | Reference\<[ValueSet](/medical-api/fhir/resources/valueset)> | Value set of normal coded values for the observations conforming to this ObservationDefinition | | abnormalCodedValueSet | No | Reference\<[ValueSet](/medical-api/fhir/resources/valueset)> | Value set of abnormal coded values for the observations conforming to this ObservationDefinition | | criticalCodedValueSet | No | Reference\<[ValueSet](/medical-api/fhir/resources/valueset)> | Value set of critical coded values for the observations conforming to this ObservationDefinition | ## Search Parameters | Name | Type | Description | Expression | | --------- | --------- | -------------------------------------------- | ------------------------------- | | code | token | The code of the observation definition. | ObservationDefinition.code | | publisher | reference | The publisher of the observation definition. | ObservationDefinition.publisher | ## 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 [ObservationDefinition](https://www.hl7.org/fhir/StructureDefinition/ObservationDefinition).