<StructureDefinition xmlns="http://hl7.org/fhir">
  <url value="https://example.org/fhir/StructureDefinition/MySpecimen" />
  <name value="MySpecimen" />
  <status value="draft" />
  <fhirVersion value="4.0.1" />
  <kind value="resource" />
  <abstract value="false" />
  <type value="Specimen" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Specimen" />
  <derivation value="constraint" />
  <differential>
    <element id="Specimen.identifier">
      <path value="Specimen.identifier" />
      <short value="External Identifier1" />
    </element>
  </differential>
</StructureDefinition>