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X12 271 response guide

Transaction context

Transaction context identifies an X12 transaction and how its business event is correlated. In a 271, ST opens the transaction set and BHT supplies the beginning-of-hierarchical-transaction context.

ST and SE

Section titled “ST and SE”

ST01 identifies the transaction set as 271. ST02 is the transaction control number, and ST03 identifies the implementation convention used in the example. SE closes the set with a segment count and the matching control number. The interchange, group, and transaction page shows the complete pair.

BHT and correlation

Section titled “BHT and correlation”

BHT appears after ST and supplies business context for the transaction:

BHT*0022*11*ELIG1010001*20990101*1201~
  • BHT01=0022 identifies the hierarchy used by this transaction.
  • BHT02=11 identifies the transaction as a response.
  • BHT03=ELIG1010001 is the reference value in this example.
  • BHT04=20990101 and BHT05=1201 record the transaction date and time.

The reference value can help correlate messages, but route documentation defines whether and how it is returned. Do not assume that it remains unchanged through every intermediary. See the public BHT field reference.