Federated Query API

The following diagram is a representation of the IHE and FHIR thoughts on the future of XCA Federated Document API. See https://confluence.hl7.org/display/GP/HL7+FHIR+Multi-domain+HIE+Architecture for more details.

To reduce uncessary lookups and solve scaling problems, an MPI is likely to be used to only call systems which are known to have patient records.