Overview
Timely Filing is each payer's contractual or regulatory deadline for receiving an initial claim. It runs from the date of service and varies from as short as 30 days (a small number of plans) to 365 days (Medicare FFS, most state Medicaid programs, some commercial plans). A claim received after the deadline is denied under CARC 29 ("The time limit for filing has expired") and the denial is generally non-appealable. Exceptions exist — retroactive eligibility backdating, payer delay, newborn enrollment, and documented clearinghouse outages are among them — but they are narrow and heavily documented.
Because the denial is usually final, timely-filing write-offs are pure revenue loss. They do not enter the denial-recovery funnel; they flow directly to bad debt. For that reason many practices track timely-filing write-offs as a distinct financial KPI rather than mixing them into the broader denial category. Monthly timely-filing write-off dollars, trended against submission-lag metrics, surface systemic problems before they compound.
Timely-filing windows vary widely by payer and by line of business. Medicare FFS is 365 days under 42 CFR §424.44. State Medicaid programs are bounded by the federal 42 CFR §447.45 one-year ceiling but most state plans set shorter windows of 90 to 180 days. Commercial plans run the spectrum — UnitedHealthcare and some BCBS licensees are 90 days for par providers, Aetna is commonly 120 days, Humana is 180 days, and Cigna is 90 days from date of service. Medicare Advantage plans typically mirror or shorten the commercial sponsor's window. Every payer record should document the timely-filing limit and cite the provider manual; values that cannot be confidently sourced should be flagged rather than guessed.
The provider's operational challenge is not the deadline itself but the cumulative effect of upstream delays. A 90-day window collapses quickly when charge lag is 10 days, coding lag is 5 days, claim-scrubbing rework is 3 days, and a payer rejection forces a resubmission after another 14 days. Secondary claims, crossed-over from primary payers after primary adjudication, also run against the secondary's filing window — which for some payers begins at the primary's remittance date rather than the original date of service. A well-run practice measures filing lag at each stage of the pipeline and intervenes before the deadline becomes the binding constraint.
When timely-filing denials do occur, the only reliable defense is documentation of the submission trail. Clearinghouse acceptance receipts (277CA), payer acknowledgements, and any evidence of a payer-side delay constitute the appeal packet. In narrow cases — retroactive Medicaid eligibility, coordination-of-benefits crossovers, or payer system outages — extensions are possible but they require rigorous documentation of when the provider learned of the eligibility, when the primary payer remitted, or when the payer's system was unavailable. Assumption of extension without documentation is a frequent cause of sustained denials.
Industry benchmark
Medicare FFS is 365 days (42 CFR §424.44). Common commercial windows: UnitedHealthcare 90 days, Cigna 90 days, Aetna 120 days, Humana 180 days (per each payer's provider manual, as published on the payer's provider portal). State Medicaid windows are set by each state plan under the 42 CFR §447.45 federal one-year ceiling — most state plans set 90–180 days.
Worked example
A practice's average claim submission lag is 12 days for a payer with a 90-day timely filing window. A single claim rejects on day 12 and is reworked on day 22. The payer rejects the resubmission for a different reason on day 36 and rework takes another 10 days. The second resubmission, on day 52, now has 38 days of runway left — still safe, but a third rejection cycle would push the claim past the deadline and create a write-off. Monitoring filing-lag distributions catches these dynamics before the write-offs materialize.
Frequently asked questions — Timely Filing
What is the Medicare timely filing limit?
365 days from the date of service under 42 CFR §424.44. Narrow exceptions exist for retroactive eligibility and certain administrative errors; most other late filings are denied finally.
Can timely filing denials be appealed?
In narrow circumstances, yes. Common exceptions include retroactive eligibility backdating, documented payer-side delays, coordination-of-benefits crossovers where the secondary payer window runs from the primary's remittance date, and documented clearinghouse outages. Each requires evidence — clearinghouse 277CA receipts, payer acknowledgements, or eligibility backdating letters. Assumptions without documentation are generally sustained on denial.
Does timely filing run from date of service or date billed?
Almost always from date of service for primary payers. For secondary payers, some plans start the clock at the primary's remittance date rather than the original service date — read each payer's secondary-claim filing language carefully. Corrected claims sometimes have a separate filing window measured from the original denial date.
How do we prevent timely filing write-offs?
Measure and reduce charge lag, coding lag, and rework lag. Submit claims daily rather than weekly. Track aging of unbilled charges and unacknowledged claims in a dedicated work queue with a cutoff well before the shortest payer deadline — for a 90-day payer, alerting at day 60 leaves actionable runway.
Disclaimer
This glossary entry is operational reference for revenue-cycle and medical-billing professionals. It is not legal, clinical, or contractual advice. Industry benchmarks cite named public sources where available; always verify against the current guidance from the authority body before relying on a number in a contract, policy, or compliance filing.