A merge has been done at the account identifier level. That is, two PID-18-patient account number identifiers have been merged into one.
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.
The patient account numbers involved may or may not have visits. A merge account - patient account number (event A41), is intended for merging account records without merging other subordinate identifiers. Any other subordinate identifiers that were previously associated with the "incorrect source account number" are now associated with the required "correct target account number." Specification of these other subordinate identifiers is not required to be provided.
This event and the message syntax do, however, allow for the specification of any other "new subordinate identifiers" (in addition to the PID-18-patient account number identifier). For those environments that may require changes to these other subordinate identifiers because of this merge account event A41 merge account - patient account number (event A41), it is required that the old and new identifiers be a "tightly coupled" pair.
Each superior identifier associated with this account identifier level should have the same value in both the PID and MRG segments.
See Section 3.5.23.5.2, "Merging patient/person information," for a discussion of issues related to the implementation of merge messages.
All data associated with the "correct target account number" are treated as updated information.
ADT ADT Message Chapter
MSH Message Header 2
EVN Event Type 3
{ PID Patient Identification 3
[ PD1] Additional Demographics 3
MRG Merge Information 3
[ PV1] Patient Visit 3
}
ACK General Acknowledgment Chapter
MSH Message Header 2
MSA Message Acknowledgment 2
[ ERR ] Error 2