Release 5 Draft Ballot
Infrastructure And Messaging Work GroupMaturity Level: N/AStandards Status: Informative
Defines "common" extensions for use with the messageheader resource and contained elements
messageheader-response-requestmessageheader-response-request :

This extension enables the capability currently available through MSH-16 (Application Level acknowledgement) in HL7 Version 2 to declare at a message instance level whether a response is required or only upon error or success, or never.