ADT^A37 — Unlink Patient Information

Cancellation of a link previously created by A24 (Link Patient Information). The MPI manager has realised the two patients are not the same person.

Purpose

A37 cancels a previous A24 (link). A24 marked two patients as the same person for contextual synchronisation, without physical merge. A37 unmakes that link. The two patient IDs become independent again.

Segment structure

Structure ADT_A37: MSH, EVN, two PIDs (1st and 2nd) to identify the two entities being unlinked.

Real-world example

Unlink MR100300 and MR100301 previously linked in error:

MSH|^~\&|MPI|HOSP01|EHR|CLINIC02|20260518120000||ADT^A37^ADT_A37|MSG00037001|P|2.5.1|||AL|NE
EVN|A37|20260518120000|||MPI003^Unlinker^Person^^^MS.|UNDO ERRONEOUS LINK
PID|1||MR100300^^^HOSP^MR||MARTIN^PIERRE^^^MR.||19720422|M
PID|2||MR100301^^^HOSP^MR||MARTIN^PAUL^^^MR.||19720420|M

Acknowledgment (ACK)

MSH|^~\&|EHR|CLINIC02|MPI|HOSP01|20260518120001||ACK^A37^ACK|ACK00037001|P|2.5.1
MSA|AA|MSG00037001

Common errors

• Single PID: A37 requires two PIDs to identify the pair being unlinked.
• A37 after an A30 (merge): A30 physically merges, no simple undo. A37 only works on A24 links.
• Audit missing: traceability is essential ("who unlinked, when, why").

Related ADT events

See also: ADT^A24, ADT^A30.