HL7 Cross-Paradigm Specification: FHIRPath, Release 1 and Edition 3

DESCRIPTION

FHIRPath is a path based navigation and extraction language, somewhat like XPath. Operations are expressed in terms of the logical content of hierarchical data models, and support traversal, selection and filtering of data. Its design was influenced by the needs for path navigation, selection and formulation of invariants in both HL7 Fast Healthcare Interoperability Resources (FHIR) and HL7 Clinical Quality Language (CQL).

The standard is available at hl7.org/FHIRPath. 

ALTERNATIVE NAMES

HL7 Cross-Paradigm Specification: FHIRPath, Release 1 and Edition 3 may also go by the following names or acronyms:

TARGETS

• Quality Reporting Agencies
•  Standards Development Organizations (SDOs)
• Regulatory Agency
• Payors
• EHR, PHR Vendors
• Health Care IT Vendors
• Clinical Decision Support Systems Vendors
• HIS Vendors
• Healthcare Institutions (hospitals, long term care, home care, mental health)

BENEFITS

• Provides the ability to easily and precisely express conditions of basic logic
• Enables technology independent description of information model paths
• Allows the same language to be used across information models

IMPLEMENTATIONS/CASE STUDIES

• HAPI,
• Firely,
• Aidbox,
• Onyx,
• Helios Software and others (FHIRPath-lab).
   

DEVELOPMENT BACKGROUND

Since the publication of the normative specification, FHIRPath feature requests have continued to drive implementation of FHIRPath engines and there is a need to update the specification with the latest feature requests and implementation guidance.

FHIRPath arose out of the need for a simple, lightweight, path-based navigation language that was independent of object representation format. Existing path-based languages were all too closely tied to the representation format (XML, JSON, etc).

In Fast Healthcare Interoperability Resources (FHIR), FHIRPath is used within the specification to provide formal definitions for conditions such as validation invariants, search parameter paths, etc. Within Clinical Quality Language (CQL), FHIRPath is used to simplify graph-traversal for hierarchical information models.

In both FHIR and CQL, the model independence of FHIRPath means that expressions can be written that deal with the contents of the resources and data types as described in the Logical views, or the UML diagrams, rather than against the physical representation of those resources. JSON and XML specific features are not visible to the FHIRPath language (such as comments and the split representation of primitives (i.e. value[x])).

The expressions can in theory be converted to equivalent expressions in XPath, OCL, or another similarly expressive language.

FHIRPath can be used against many other graphs as well. For example, Use of FHIRPath on HL7 Version 2 messages describes how FHIRPath is used in HL7 v2.

RELATED DOCUMENTS

HL7 Cross-Paradigm Specification: FHIRPath, Release 1 and Edition 3

STU DOCUMENTS

HL7 Cross-Paradigm Specification: FHIRPath, Edition 3 See the standard at http://hl7.org/fhirpath/STU3.

(Submit Feedback on STU)

ADDITIONAL DETAILS

• JavaScript: http://niquola.github.io/fhirpath-demo/#/
• Java RI: In the FHIR build tooling at org.hl7.fhir.dstu3.utils.FHIRPathEngine
• Pascal RI: https://github.com/grahamegrieve/fhirserver/blob/master/reference-platform/dstu3/FhirPath.pas
• .NET RI: https://github.com/ewoutkramer/fhir-net-fhirpath

TOPIC

• Decision Support

BALLOT TYPE

• Normative
• STU

STATUS DATE

2020-01-16

RESPONSIBLE WORK GROUP

PRODUCT TYPE

• Methodology Specifications

STAKEHOLDERS

• Clinical Decision Support Systems Vendors
• EHR, PHR Vendors
• Health Care IT Vendors
• Healthcare Institutions
• HIS Vendors
• Payors
• Quality Reporting Agencies
• Regulatory Agency
• Standards Development Organizations (SDOs)

FAMILY

• Cross-paradigm

CURRENT STATE

• Active

REALM

• Universal