Project Overview

The intent of the project is to update the conformance methodology used to profile message definitions and to separate (divorce) the conformance chapter (currently Chapter 2B) from the “main” HL7 v2 standard.

  • Provide an independent (separate) HL7 v2 Conformance Methodology standard.
  • Update the conformance constructs and profiling mechanisms used for implementation guide creation
  • Update the profile schema that supports the XML computable representation for implementation guides and message profiles
  • Deprecate by means of an errata the Conformance chapter/section from all prior V2 versions. (our expectation is that the content of conformance testing of existing IGs will not change, but going forward any new specification will use this updated conformance methodology). To be clear, the proposal is an updated method of how to specify conformance for new IGs.
  • Identify opportunities to encourage adoption by external implementation guide developers (e.g., IHE) to use the same conformance definitions and constructs.

There are many versions of the HL7 v2 standard. An explicit conformance methodology was introduced into the standard in version 2.5 and revised in subsequent versions of the standard. The conformance methodology was part of chapter 2 initially and later became a subchapter (Chapter 2B Conformance).  This document serves to replace (override) the conformance methodology in these earlier versions and it is intended to be applied to any HL7 v2 version. That is, if a developer is seeking to constrain a version 2.5.1 message event, they should use the conformance methodology prescribed in this document and not the conformance methodology given in version 2.5.1.

Project Need

HL7 v2 implementation guide specification has historically been ambiguous due to the lack of sufficient conformance profiling mechanisms and guidance. In recent years many updates and improvements have been developed and used in the creation of HL7 v2 implementation guides. However, these practices have not been formally documented in the HL7 v2 conformance chapter. Additionally, the profile schema that provides the format of the computable XML profile has not been updated. The need is to provide a formal specification for both the narrative and machine representation of current best practices of the HL7 v2 conformance methodology.

Conformance and profiling of message definitions is independent of any one version of the HL7 v2 standard. Profiling activities should use the current conformance mechanisms for creating implementation guides. Currently, the conformance methodology is embedded in each v2 version. The need is to create and promote a process to use the latest profiling constraint mechanisms irrespective of the version of the HL7 v2 implementation guide.  Considering that v2 is expected to be relevant due to the global install base, and it has been recognized that consistent, clear implementation guides are essential to the success of any wide ranging interoperability initiative, maintaining current conformance definitions and practices is critical.


Under this page their are a number of topics that will make up the updated conformance methodology specification. The intent of these pages is to present the topic, the current write-up and to seek comments.

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