What CO-29 means
The claim was received after the payer's timely filing limit.
The CO group code means this amount is a contractual obligation: under most contracts you cannot bill it to the patient.
Common causes
- Claim submitted late
- Original submission rejected and never resubmitted
How to fix it
- Appeal only with proof of timely filing, such as clearinghouse acceptance reports
- Submit daily and track rejections to prevent this
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.