If the interaction, as indicated by the interaction identifier in the HL7 transmission wrapper, indicates that the initiating system also requires an application response (a.k.a. application acknowledgment, functional response, or query response), this can be returned as an immediate response or as the initial message of a later (or deferred) exchange.
For the Application Response, the receiving system acts as the initiator. Since the interaction the receiving system sends is application-specific, the models of these application-level response interactions are defined in the relevant application-specific domain. Whether an application response may request another application acknowledgement interaction, is dependent on the design of the message interaction sequence as defined in the relevant application-specific domain.
- Application-level response interactions are sent to the RespondTo device as contained in the Transmission Wrapper of the initial interaction. If the RespondTo class is not present in the initial interaction is not used, the response interaction will be sent to the Sender device.
- An Application Response is also known as an Application Acknowledgement, an Application Ack and an Application Level Acknowledgement.