Embedding FHIR in Medical PDF: A Migration Path for Interoperable Documentation.

Introduction: Medical services routinely transmit patient data using PDF, even as FHIR emerges as the standard for structured healthcare interoperability. This mismatch reflects a broader fragmentation in digital documentation, where pragmatic workflows often outpace technical ideals.

Methods: We propose embedding FHIR bundles into PDF to enable structured data reuse without disrupting established processes. These hybrid documents can be processed via FHIR Binary endpoints, allowing downstream systems to extract, validate, and map the embedded data to interoperable resources.

Results: A proof-of-concept using German emergency medical services records demonstrates that vital parameters and timestamps can be transmitted as PDF while preserving machine-readable structure.

Conclusion: This approach respects existing transport mechanisms and accommodates heterogeneous IT landscapes. By bridging legacy formats with modern standards, the method offers a scalable migration path toward interoperability-ready to deploy wherever PDF are already in use. Thus, our approach provides a migration pathway for integrating routine data into interoperable research infrastructures, enabling structured reuse without altering clinical workflows.