ITK3 Test Harness - user guidance

The NHS England Interoperability Standards Service has developed a set of generic Fast Healthcare Interoperability Resources (FHIR) messaging components to allow a standardised approach to using FHIR message headers and responses across NHS message and document flows in England. These components, along with NHS England FHIR message and FHIR document specifications, are part of the ITK3 solution.

View the message specification and implementation guide

View specifications describing a specific payload, in this case Transfer of Care, that could be carried by the ITK3 FHIR messaging components

FHIR messages will be sent using Message Exchange for Social Care and Health (MESH) from sender to recipient as per the ITK3 specifications. To ensure that senders are clear on the successful receipt or otherwise of their messages, a piece of software, a Test Harness, has been built to produce standard
responses, including failures of messages.

Standard error codes and descriptions will be returned depending on the nature of the success/failure of a message. View details of expected response codes

The ITK3 Test Harness simulates the expected responses of a receiving primary care practice system and the behaviour of a hospital sending system. The ITK3 Test Harness is situated within the Integration environment.

The transport mechanism used is MESH.

More detailed information about the ITK3 Test Harness

This document is intended for ITK3 message specification implementers who wish to access the ITK3 Test Harness to confirm the validity of their messages and to check that the various responses returned by the ITK3 can be correctly catered for.

Use of MESH Client does not require any additional onboarding.

Use of MESH-API requires completion of the MESH-API onboarding process prior to ITK3 Test Harness use. See Message Exchange for Social Care and Health (MESH) API - NHS England.

The prerequisites for use of the ITK3 Test harness are:

1. Access to MESH in INT environment.
2. Ownership of a MESH mailbox in INT environment.

See Integration environments - NHS England for access details

Users may also wish to:

• receive test harness validation reports via email
• gain access to the INT portal to view validation reports and logs
• transmit messages from the INT portal to their own test mailbox

Validation report mailing and INT Portal access will be configured as part of the onboarding process.

For further guidance on transmitting ITK3 messages via the INT Portal see Sending ITK3 MESH messages from the NHSE Messaging Portal.

Users may require additional support constructing messages, such as:

• XML valid messages
• messages which conform to the NHS Digital message specifications

There are several validation tools available which support implementers in creating valid and profile conformant messages.

The FHIR website has a section concerning validation; a variety of validation tools for general use can be downloaded from this area.

Additional validation tools can be obtained from the FHIR community, including clarotech.

Guidance to creating valid and conformant messages is available by emailing [email protected].