Timely Filing
Definition
Timely filing is the deadline by which a medical claim must be submitted to the payer after the date of service. Medicare's deadline is 365 days. Commercial payers set their own limits: UnitedHealthcare allows 90 days in-network; Anthem allows 180 days (varies by state). Missing the timely filing deadline results in permanent claim denial — the revenue is lost and cannot be recovered through appeal.
Why Timely Filing Matters
Timely filing denials are hard denials. Once the window closes, the claim is dead. CO-29 is the CARC code for timely filing denials. Unlike coding errors or missing modifiers, timely filing denials have no remedy. Tracking deadlines by payer prevents what is often the most expensive category of preventable revenue loss in a billing operation.
How Timely Filing Works
The clock starts on the date of service (DOS). Each payer has a different deadline. Medicare: 365 days from DOS. UHC: 90 days in-network, 180 days out-of-network. Anthem: 180 days (varies by state). Aetna: 90 days in-network, 180 days OON. Cigna: 90 days from DOS. State laws add another layer — some states require faster submission. See timely filing regulations for the full federal and state framework.
Related Terms
Claim denial — the result of missing the deadline. Clean claim — a correctly submitted claim that starts the payer's processing clock. Appeal process — not available for timely filing denials in most cases. Remittance advice — where CO-29 appears.
Common Questions
Does the timely filing clock reset if a claim is denied and resubmitted?
No. The original date of service is always the reference point. If a claim is denied for a correctable reason (wrong modifier, missing info), you still must resubmit within the original timely filing window. Track the original DOS for every claim in your AR system.
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This glossary is for informational purposes. Consult official billing guidelines and payer policies for definitive definitions. Last updated: 2026-04-06.