- We will leverage the ongoing work from the O&O HL7v2-to-FHIR mapping project where possible, however PDex will have its variations for a number of reasons:
- The HL7v2-to-FHIR worksheet mappings contain segments from HL7v2.7 (e.g.: PRT). Most HL7v2 messages received by payers in our use case are v2.5.1 or v2.3.
- PDex will align with US Core R4 which will impose further constraints on cardinality and coding systems not in these mappings.
- Payer-relevant elements and coding systems may further extend or constrain the FHIR target mappings.
- HL7v2.5.1 will be the source data standard which will be mapped to FHIR. While there are other more recent versions of HL7v2, version 2.5.1 is cited for CLIA conformance.
- Semantic mappings might be approximate in cases where the term descriptions are ambiguous.
- Structural mappings might not align in several ways noted below:
- data type
- non-existent elements