description: This extension allows a Reference to a Composition resource instance that provides structure for organizing the contents of the DiagnosticReport. package_name: fhir.r4.ukcore.stu3.currentbuild derivation: constraint name: ExtensionUKCoreDiagnosticReportComposition type: Extension elements: url: pattern: {type: uri, value: 'http://hl7.org/fhir/5.0/StructureDefinition/extension-DiagnosticReport.composition'} type: uri index: 0 value: short: Reference to a Composition resource for the DiagnosticReport structure choices: [valueReference] index: 2 valueReference: type: Reference short: Reference to a Composition resource for the DiagnosticReport structure choiceOf: value refers: ['http://hl7.org/fhir/StructureDefinition/Composition'] index: 3 package_version: 0.0.18-pre-release class: extension kind: complex-type url: http://hl7.org/fhir/5.0/StructureDefinition/extension-DiagnosticReport.composition base: http://hl7.org/fhir/StructureDefinition/Extension version: 1.1.0 required: [value, valueReference]