HL7 ACK

ACK - Acknowledgment
In HL7, when an receiving application receives a business message, it is expected to send the ack back to sending application.

The acknowledgment generation is dependent on the value in the MSH.15 of the incoming business message. The standard values are

NE : Never
AL : Always
SU : Successfully processed
ER : Only during Error


Structure of HL7 ACK
MSH - Message header, Mandatory Segment
MSA - ACK Segment, Mandatory Segment
ERR - Error Segment, Optional


Anatomy of ACK
MSH - Details about the message such as Message Type, Sending, receiving application, date.

MSA - Contains the summary of issues or processing details

• MSA.1 - Code explaining Accept(AA, CA), error(AE, CE) or Reject(AR, CR)
• MSA.2 - Contains the control number of incoming business message. i.e., MSH.10 of business message
• MSA.3 - Optional field containing the error description.

ERR - Optional segment containing erroneous segment detials


Example
MSH|^~\&|HIS|System|Hosp|HL7 Genie|20071016055244||ACK^A01|A234242|P|2.3.1|
MSA|AA|234242|Message Received Successfully|