<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="BARSMessageHeaderServiceRequestResponse" />
  <url value="https://fhir.nhs.uk/StructureDefinition/BARSMessageHeader-servicerequest-response" />
  <version value="1.0.3" />
  <name value="BARSMessageHeaderServiceRequestResponse" />
  <title value="BARS MessageHeader - ServiceRequest-Response" />
  <status value="active" />
  <date value="2023-03-08" />
  <description value="BARSMessageHeader ServiceRequest Response profile" />
  <fhirVersion value="4.0.1" />
  <kind value="resource" />
  <abstract value="false" />
  <type value="MessageHeader" />
  <baseDefinition value="https://fhir.hl7.org.uk/StructureDefinition/UKCore-MessageHeader" />
  <derivation value="constraint" />
  <differential>
    <element id="MessageHeader.event[x].system">
      <path value="MessageHeader.event[x].system" />
      <fixedUri value="https://fhir.nhs.uk/CodeSystem/message-events-bars" />
    </element>
    <element id="MessageHeader.event[x].code">
      <path value="MessageHeader.event[x].code" />
      <comment value="This will be a set of fixed values that are used to trigger use case specific processing when the bundle is received (refer to guidance for definitions etc..)" />
      <min value="1" />
      <fixedCode value="servicerequest-response" />
    </element>
    <element id="MessageHeader.destination">
      <path value="MessageHeader.destination" />
      <min value="1" />
    </element>
    <element id="MessageHeader.destination.receiver.reference">
      <path value="MessageHeader.destination.receiver.reference" />
      <min value="1" />
    </element>
    <element id="MessageHeader.sender.reference">
      <path value="MessageHeader.sender.reference" />
      <min value="1" />
    </element>
    <element id="MessageHeader.sender.identifier.assigner.reference">
      <path value="MessageHeader.sender.identifier.assigner.reference" />
      <min value="1" />
    </element>
    <element id="MessageHeader.source.extension">
      <path value="MessageHeader.source.extension" />
      <slicing>
        <discriminator>
          <type value="value" />
          <path value="url" />
        </discriminator>
        <rules value="open" />
      </slicing>
      <min value="0" />
    </element>
    <element id="MessageHeader.source.extension:myExtension">
      <path value="MessageHeader.source.extension" />
      <sliceName value="myExtension" />
      <min value="0" />
      <type>
        <code value="Extension" />
        <profile value="https://fhir.nhs.uk/StructureDefinition/CDSSExtension" />
      </type>
    </element>
    <element id="MessageHeader.source.endpoint">
      <path value="MessageHeader.source.endpoint" />
      <comment value="Value used to direct response workflow" />
    </element>
    <element id="MessageHeader.reason">
      <path value="MessageHeader.reason" />
      <min value="1" />
    </element>
    <element id="MessageHeader.reason.coding.system">
      <path value="MessageHeader.reason.coding.system" />
      <fixedUri value="https://fhir.nhs.uk/CodeSystem/message-reason-bars" />
    </element>
    <element id="MessageHeader.response">
      <path value="MessageHeader.response" />
      <min value="1" />
    </element>
    <element id="MessageHeader.focus.reference">
      <path value="MessageHeader.focus.reference" />
      <min value="1" />
    </element>
  </differential>
</StructureDefinition>