CO-29: Timely Filing Deadline Exceeded
CO (Contractual Obligation)What is CO-29?
CO-29 is a Contractual Obligation code indicating the claim was not received within the payer's timely filing deadline. Filing deadlines range from 90 days (Cigna) to 365 days (Medicare) from the date of service. This denial is preventable with proper claim tracking.
Why Does CO-29 Occur?
- Claim not submitted within the payer's filing window. Each payer sets different deadlines: Cigna at 90 days, Aetna at 90 days in-network, UHC and Anthem at 180 days, Medicare at 365 days.
- Clearinghouse rejection not caught. The original claim was rejected at the clearinghouse level but the rejection was missed, and by the time it was resubmitted, the deadline had passed.
- Coordination of benefits delay. The primary payer took longer than expected, pushing the secondary claim past its filing deadline.
- Incorrect payer on initial submission. The claim was sent to the wrong payer first, and by the time it reached the correct payer, the deadline had lapsed.
How to Fix CO-29 Denials
- Check the date of service against the payer's filing deadline. If the claim was filed on time, gather proof: clearinghouse transmission report, 277CA acknowledgment, or payer portal submission confirmation.
- For commercial payers, file an appeal within the payer's appeal window (60-365 days depending on the payer) with proof of timely filing attached.
- For Medicare CO-29 denials, submit a reopening request to the MAC. Medicare CO-29 denials require a reopening request, not a standard redetermination.
- If the delay was caused by COB, submit documentation showing when the primary payer adjudicated and that the secondary was filed promptly after.
- Set up automated filing deadline alerts in your PM system to prevent future CO-29 denials.
CO-29 by Payer
| Payer | Common RARC | Appeal Deadline | Notes |
|---|---|---|---|
| UnitedHealthcare | N/A | 60 days from remittance | Filing deadline: 90 days in-network, 180 days OON. Submit reconsideration within 60 days of remittance with proof of timely filing. |
| Anthem | N/A | 365 days from denial notice | Filing deadline: 180 days (varies by state). COB exception if primary took longer than 60 days. |
| Aetna | N/A | 180 days from denial | Filing deadline: 90 days in-network. Strict enforcement. COB exceptions only. |
| Cigna | N/A | 180 days from denial | Filing deadline: 90 days. Submit appeal with clearinghouse transmission proof. |
| Medicare | N/A | 120 days (redetermination at MAC) | Filing deadline: 365 days. CO-29 denials require reopening request, not standard redetermination. |
Related CARC Codes
If you are seeing CO-29, check these related codes: CO-42 (claim timing issue), CO-22 (coordination of benefits), CO-55 (claim received out of order).
Common Questions About CO-29
Can I appeal a CO-29 timely filing denial?
Yes, if you have proof the claim was filed on time. Clearinghouse transmission reports and 277CA acknowledgments are the strongest evidence. Commercial payers allow 60-365 days to appeal. Medicare CO-29 denials require a reopening request rather than a standard redetermination.
What are the filing deadlines by payer?
Cigna: 90 days. Aetna: 90 days in-network, 180 days OON. UnitedHealthcare: 180 days. Anthem: 180 days (varies by state). Medicare: 365 days from date of service.
What if the delay was caused by another payer?
If the primary payer delayed adjudication and caused the secondary filing deadline to lapse, submit COB exception documentation showing the primary's adjudication date and your prompt secondary filing.
Altair catches CO-29 denials before submission with automated filing deadline tracking. See how pre-submit claim scoring works.