HL7 Cross-Paradigm Specification: FHIRPath, Release 1

In healthcare information systems, formal representation of logic is critical. FHIRPath is a path-based navigation and extraction language, somewhat like XPath. In FHIRPath, operations are expressed in terms of the logical content of hierarchical data models, and support traversal, selection and filtering of data. FHIRPath’s design was influenced by the need for path navigation, selection and formulation of invariants in both HL7 Fast Healthcare Interoperability Resources (FHIR) and HL7 Clinical Quality Language (CQL).

Main sections:

· Navigation model

· Path selection

· Expressions

· Functions

· Operations

· Aggregates

· Lexical elements

· Environment variables

· Types and reflection

· Type safety and strict evaluation

· Formal specifications

· Appendix A: Use of FHIRPath on HL7 version 2 messages

· Appendix B: FHIRPath tooling and implementation