As describes in Default Service section, the FHIR resources which contain "RAD" as "serviceCategory" will be handle by the Radiology Service.
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Radiology Service handler is handling incoming request in a different manner. When I get the RadiologyHandler gets a GET request, first it 'll search searches for matching resource in the OpenMRS storage. If it's not able to find the given resource, then OpenMRS FHIR module will make makes client request to a specified external FHIR server and store received retrieve matching FHIR DiagnosticReports in OpenMRS storage and response back to the user with received FHIR DiagnosticReports.
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