Insight
A timely filing limit is the deadline by which a claim must first reach the payer. Miss it and the balance is generally unrecoverable — denied as CO-29 and written off, regardless of whether the service was legitimate, documented and medically necessary. Limits are set by contract and vary widely between payers; for Medicare fee-for-service the limit is set in statute at one calendar year from the date of service. A separate and usually much shorter clock governs appeals, running from the date of the remittance advice rather than the date of service.
The first clock governs initial submission and runs from the date of service. The second governs appeals and runs from the date of the remittance advice that communicated the denial. The second is usually much shorter. This is where recoverable money is most often lost: a claim is filed comfortably inside the filing limit, denied, then sits in a queue while the appeal window closes. The claim was never late in the sense practices worry about, and the balance is gone anyway. Any denial worklist that is not sorted with the appeal deadline visible is losing balances that were entirely recoverable.
When a patient has more than one plan, the secondary claim generally cannot be filed until the primary has adjudicated. If the primary is slow, or if the claim went to the wrong payer first and had to be redirected, the secondary payer's clock has been running the entire time. Filing to the wrong payer does not pause or reset the correct payer's limit. This is why CO-109 denials — wrong payer or wrong contractor — deserve immediate attention rather than routine queuing: every day spent discovering the error is a day subtracted from the window that still applies.
When a payer asserts a claim arrived late and the practice believes otherwise, the dispute turns on evidence. What generally satisfies a payer is electronic acknowledgement showing the claim was received on a given date — clearinghouse acceptance reports and payer acknowledgement transactions. What generally does not is an internal screenshot showing the claim was created, or a submission log the payer cannot verify. Practices that discard clearinghouse acknowledgements, or cannot retrieve them beyond a short retention window, lose disputes they would otherwise win.
Claims rarely miss a deadline through a single obvious failure. They miss it through accumulation: a charge entered late, a claim held for documentation that nobody chased, a rejection that was never worked because rejections sit outside the denial queue, a claim filed to a payer the patient had already left. Each delay is individually small and individually defensible. Together they consume a limit. The structural defence is a worklist ordered by remaining days rather than by balance or by age, so that the claims closest to becoming unrecoverable surface first.
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FAQ
For Medicare fee-for-service, claims must be filed within one calendar year of the date of service. This limit is set in statute rather than by contract. Medicare Advantage plans are administered by private payers and set their own limits, which is a frequent source of confusion.
Sometimes, where the practice can evidence that the claim was in fact submitted on time or that a payer error caused the delay. Success depends on documentary proof — clearinghouse acknowledgements and payer acknowledgement transactions. Without that evidence, appeals of CO-29 rarely succeed.
No. The limit applies to the original receipt of the claim by the payer. Resubmission does not create a new starting point, and a claim resubmitted after the limit will deny as untimely even though the resubmission itself was recent.
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