Implement coordination of benefits (COB) in an X12 837 claim by populating Loop 2320 with primary payer adjudication data

Verified steps

1. Confirm COB scenario: obtain the primary payer's EOB or 835 ERA showing the paid, adjusted, and patient responsibility amounts before building the secondary claim
2. In the 837P or 837I, after the primary subscriber loop (Loop 2000B), add Loop 2320 (other subscriber information) for each additional payer: populate OI segment (other insurance information, OI03 benefits assignment certification), NM1*IL (other subscriber name), and N3/N4 address if required by the secondary payer
3. In OI segment set OI06 (release of information code) to 'Y'; set COB claim-level data in AMT segments within Loop 2320: AMT*D (COB payer paid amount from primary), AMT*EAF (remaining patient liability), AMT*A8 (credit/debit amount)
4. At the service line level add Loop 2430 (line adjudication information) for each SV1/SV2 line: SVD segment with SVD01 (other payer ID), SVD02 (service paid amount by primary), SVD03 composite (procedure code), SVD05 (units paid), then CAS segment for primary payer adjustments using CARC codes
5. Include DTP*573 (claim adjudication date from primary EOB) within Loop 2320 and DTP*573 within Loop 2430 at the line level to satisfy secondary payer requirements for timely COB data
6. Submit to the secondary payer via clearinghouse; verify the secondary's companion guide for whether they require Loop 2320 at the claim level, Loop 2430 at the line level, or both