What CO-129 means
Information about prior payer processing on the claim is inconsistent.
The CO group code means this amount is a contractual obligation: under most contracts you cannot bill it to the patient.
Common causes
- Wrong primary payment or adjustment amounts on a secondary claim
How to fix it
- Check the primary EOB/ERA amounts
- Correct the COB information and resubmit
Check the remark code (RARC) that came with the denial and the payer's own policy, since rules vary by payer and plan. This is a plain-English summary written by GetMax; the official code text is published by X12 at x12.org/codes.
Prevent it next time
Most denials are caused before the claim is sent. See 12 ways to reduce claim denials, or let our denial management team work them for you.