{
  "resourceType": "StructureDefinition",
  "id": "itcc-core-specimen-age-ext",
  "url": "https://www.itcc-consortium.org/fhir/StructureDefinition/itcc-core-specimen-age-ext",
  "version": "0.4.0",
  "name": "ITCCCoreSpecimenAgeExt",
  "title": "ITCC Specimen Age (Months) Extension",
  "status": "active",
  "date": "2026-02-27",
  "publisher": "ITCC Consortium",
  "description": "Extension to record patient age in months at the time the specimen was extracted.",
  "fhirVersion": "4.0.1",
  "kind": "complex-type",
  "abstract": false,
  "type": "Extension",
  "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension",
  "derivation": "constraint",
  "differential": {
    "element": [
      {
        "id": "Extension",
        "path": "Extension",
        "short": "Age at specimen extraction (months)",
        "min": 0,
        "max": "1"
      },
      {
        "id": "Extension.url",
        "path": "Extension.url",
        "min": 1,
        "max": "1",
        "fixedUri": "https://www.itcc-consortium.org/fhir/StructureDefinition/itcc-core-specimen-age-ext"
      },
      {
        "id": "Extension.value[x]",
        "path": "Extension.value[x]",
        "min": 1,
        "max": "1",
        "type": [
          {
            "code": "Quantity"
          }
        ]
      },
      {
        "id": "Extension.valueQuantity.value",
        "path": "Extension.valueQuantity.value",
        "min": 1,
        "max": "1"
      },
      {
        "id": "Extension.valueQuantity.system",
        "path": "Extension.valueQuantity.system",
        "min": 1,
        "max": "1",
        "fixedUri": "http://unitsofmeasure.org"
      },
      {
        "id": "Extension.valueQuantity.code",
        "path": "Extension.valueQuantity.code",
        "min": 1,
        "max": "1",
        "fixedCode": "mo"
      },
      {
        "id": "Extension.valueQuantity.unit",
        "path": "Extension.valueQuantity.unit",
        "min": 0,
        "max": "1"
      }
    ]
  }
}