CO-29: Timely filing deadline has expired
CO-29 means the claim was submitted after the payer's filing window (often 90 - 365 days from the date of service). This is a provider-side denial - the patient is generally not responsible for balances created by a late claim.
Why this denial happens
- The provider's billing system delayed the claim past the payer's window.
- The claim was bounced once for a fixable error and not resubmitted in time.
- Insurance changed mid-year and the claim was sent to the prior payer.
How to fix or appeal CO-29
- Ask the billing office for proof of timely filing - they often have it and just need to resubmit it.
- If they don't, ask them to write off the balance; under most provider contracts CO-29 cannot be billed to the patient.
- If you receive a balance bill, dispute it in writing citing the CO-29 EOB.
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