Use IHE PDQm (Patient Demographics Query for Mobile) to search for a patient across health information exchange participants using FHIR Patient search parameters
Send a GET /Patient request with multiple demographic search parameters: family, given, birthdate, and identifier to the PDQm Patient Demographics Supplier endpoint
Include _format=application/fhir+json and handle the returned searchset Bundle; iterate entries to evaluate match quality
Use the match-grade extension on each Patient entry to determine whether the result is certain, probable, or possible
Handle the case where too many results are returned (OperationOutcome with code too-costly) by narrowing the search with additional parameters
Use the returned Patient.id only within the domain of the responding server; do not assume the ID is portable to other systems without identifier-based cross-referencing
Known gotchas
PDQm does not mandate fuzzy matching; the degree of demographic matching is implementation-specific, so exact search parameters may return zero results even when a patient exists with slightly different name casing
The match-grade extension URL must be checked in the returned Bundle entry search object, not in the Patient resource itself; not all servers populate this extension
PDQm responses may include patients from multiple domains with different identifier systems; always inspect the identifier system to determine which MPI or domain each returned patient belongs to before acting on the result
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp