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Interoperability Tool Kit (ITK) specification versions

ITK3 Messaging Distribution specification versions

Directory of published ITK3 Messaging Distribution versions


“ITK3 Messaging Distribution” is the term used for a set of generic FHIR messaging components. These messaging components have been developed by NHS Digital to allow a standard approach to FHIR MessageHeaders and responses (acknowledgements) across NHS message and document flows in England. The Payloads are not specified within this specification as these components can carry any Payload. These components, along with NHS Digital FHIR Message and FHIR Document specifications are part of the ITK3 solution.

Beta implementable specification versions

The table below contains the beta versions of the ITK3 Message Distribution specifications.

All versions are based on the FHIR® STU3 standard.


Status Release Version Release Date Details
ITK3 Message Distribution Specifications
beta ITK3 2.5.1-beta 17th August 2018 Current beta version of the specification for ITK3.

Warning: beta specifications are still subject to some changes, but these changes will be done under a RFC / CCN process and with consultation with first of type vendors.

Previous ITK Versions

The table below contains the Live version of the ITK 2.2 specification.

These specifications are deemed to be stable enough for implementations.

All versions are based on the HL7 V3 standard.

Status Release Version Release Date Details
ITK 2.2 – Overview
live ITK 2.2-Live May 2016 Overview of ITK 2.2
ITK 2.2 – Specifications
live ITK 2.2 architecture specifications May 2016 ITK 2.2 full specifications

Associated Specifications

Item Name Description Link
Transfer of Care Document Payloads Transfer of Care payloads that can be sent via ITK3. TOC Payloads

Development and Testing Tooling

Item Name Description Link
Clinical Assurance Tool (CAT) A tool for developers to allow rendering of FHIR documents for internal checking and assurance. Clinical Assurance Test Tool
ITK3 Test Harness A synthetic receiver of ITK3 Documents and Messages that supports the response and error behaviour defined in the ITK3 Message Distribution specification. ITK3 Test Harness