ADT/ACK - Merge account - patient account number

An A41 event is used to signal a merge of records for an account that was incorrectly filed under two different account numbers. The _incorrect source patient account number_ identified in the MRG segment (MRG-3 - Prior Patient Account Number) is to be merged with the _correct target patient account number_ identified in the PID segment (PID-18 - Patient Account Number). The _incorrect source patient account number_ would then logically never be referenced in future transactions. It is noted that some systems may still physically keep this _incorrect identifier_ for audit trail purposes or other reasons associated with database index implementation requirements.