description: Provides a reason why the expected value or elements in the element that is extended are missing. package_name: rs/pcr.r4.1 derivation: constraint name: DataAbsentReason type: Extension elements: url: pattern: {type: uri, value: 'http://hl7.org/fhir/StructureDefinition/data-absent-reason'} type: uri index: 0 value: choices: [valueCode] index: 2 valueCode: {type: code, choiceOf: value, index: 3} package_version: 1-0-pkg-1.2.4 class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/data-absent-reason base: http://hl7.org/fhir/StructureDefinition/Extension version: 4.0.1 required: [value, valueCode]