ACK_A18
3.2.18 ADT/ACK - merge patient information (event A18)
3 segments
Event A18 is being retained for backward compatibility. The A18 event is used to merge current and previous patient identification numbers: PID-3-patient ID ( internal ID), PID-2-patient ID (external ID), PID-4-alternate patient ID-PID, and PID-18-patient account number. This procedure is required, for example, when a previous patient is registered under a new patient identification number because of an error, or because there was insufficient time to determine the actual patient identification number. The merge event occurs when a decision is made to combine the information under either the new or the old identifier(s). We recommend that events A34 (merge patient information-patient ID only), A35 (merge patient information-account number only), A36 (merge patient information-patient ID and account number), A39 (merge person-external ID), A40 (merge patient-internal ID), A41 (merge account-patient account number), and A42 (merge visit-visit number) be utilized in place of the A18 event whenever possible.
The PID segment contains the surviving patient ID information. The MRG segment contains the non-surviving information.
Message Structure
3 segments
R RequiredO Optional Choice
MSH
R1MSA
R1ERR
O1