Current estimates are that billions of C-CDA clinical documents are exchanged annually in the United States. To make this data easier to use and integrate with newer FHIR R4 US CORE conformant resources, the Cross Group Project workgroup (https://confluence.hl7.org/display/CGP/Cross-Group+Projects+Home) launched a project (https://confluence.hl7.org/display/CGP/C-CDA+to+and+from+US+Core+Mapping) to develop a mapping between the standards. This also includes the ability to take US CORE conformant FHIR resources and present that information in C-CDA clinical documents. The work to date has created multiple spreadsheets and informative guidance on this process.
In the meantime, various HealthIT vendors have started developing their own mappings to satisfy the popular demands to use C-CDA documents for FHIR use cases and vice versa. In an effort to align these mappings in the field as much as possible and to provide additional guidance using examples, we have started an effort to have multiple vendors map from the same single CCD inbound document and share their mapped FHIR resources for cross comparisons. We set up a github repo to host the common inbound CCD as well as the mapped FHIR resources by various vendors: https://github.com/chunli866/CCDAtoFHIRSamples. We hosted a series of weekly calls with various industry vendors (e.g., Diameter Health, Google, MDIX) to discuss the mapping results and the minutes are kept here: Example-driven C-CDA-to-FHIR mapping weekly discussion minutes. We have also hosted a track at the 31 FHIR Connectathon (2022 - 09 C-CDA to FHIR Mapping). The attendees include leaders in the Standards Community, as well as industry leaders who have done their mappings. The full list is here: . The Report out that summarized the discussions, learnings and next steps is here: https://docs.google.com/document/d/1Foc4GdI_IvHZGmyJixlUfS2si6ADclyJMDs8qKhKQj0/edit#heading=h.ytop3leewum6.
If you have any questions, or are interested in joining these efforts (access to the github repo, join weekly calls, etc.), feel free to contact Chun Li at firstname.lastname@example.org.