<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="Referral-Identifier-EXT" />
  <url value="http://fhir.infoway-inforoute.ca/io/CA-eReC/StructureDefinition/Referral-Identifier-EXT" />
  <name value="ReferralIdentifier" />
  <status value="draft" />
  <description value="For requisitions this extension is used to convey the ServiceRequest.requisition identifier in the message header." />
  <fhirVersion value="4.0.1" />
  <kind value="complex-type" />
  <abstract value="false" />
  <context>
    <type value="element" />
    <expression value="MessageHeader" />
  </context>
  <type value="Extension" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Extension" />
  <derivation value="constraint" />
  <differential>
    <element id="Extension">
      <path value="Extension" />
      <definition value="For requisitions this extension is used to convey the ServiceRequest.requisition identifier in the MessageHeader." />
      <min value="0" />
      <max value="1" />
    </element>
    <element id="Extension.extension">
      <path value="Extension.extension" />
      <max value="0" />
    </element>
    <element id="Extension.url">
      <path value="Extension.url" />
      <fixedUri value="http://fhir.infoway-inforoute.ca/io/CA-eReC/StructureDefinition/Referral-Identifier-EXT" />
    </element>
    <element id="Extension.value[x]">
      <path value="Extension.value[x]" />
      <min value="1" />
      <type>
        <code value="Identifier" />
      </type>
    </element>
  </differential>
</StructureDefinition>