A claim denied for timely filing is the one denial you cannot argue your way out of. The deadline runs from the date of service on almost every original claim, and it keeps running while the account sits in a work queue. Payer windows range from 95 days to a full calendar year, and the only version that matters is the one written down before the work started.
What this covers
- Medicare fee-for-service allows 12 months from the date of service, and the receipt date decides whether the claim was on time.
- Texas Medicaid allows 95 days from the date of service; Medi-Cal allows six months following the month of service.
- A Medicare late-filing denial is not an appealable determination, so the four CMS exceptions are the only route back.
- Corrected claims, secondary claims and appeals each run on their own clock, and those clocks often start at the remittance advice.
- Put the deadline on the claim at registration, not at the point of denial, with an internal target at 75 percent of the window.
A claim is filed when the payer receives it, not when your clearinghouse says it left.Medicare counts receipt, and a weekend upload moves to the next business day.
Most practices can tell you their largest payer by volume. Far fewer can tell you that payer’s filing limit without opening a manual. That gap is expensive, because the limit is the only deadline in the revenue cycle that ends the conversation.
The clock starts on the date of service, not the date you noticed
Every filing limit in this article runs from a service date, a discharge date or a remittance date. None of them run from the day a claim failed an edit, or the day a patient called about a balance. A practice that discovers a missing authorization in month three has already spent a quarter of a 12-month window, and all of a 95-day one.
Medicare states the rule plainly. Under 42 CFR 424.44, fee-for-service claims must reach the Medicare Administrative Contractor within 12 months, or one calendar year, of the date services were furnished. For a professional claim with span dates, the line item From date sets the clock. For an institutional claim, the Through date does, so an inpatient stay billed on the discharge date starts later than a clinic visit on the same calendar day.
- A February 29 date of service must be filed by February 28 of the following year.
- Electronic claims received after 6 p.m. ET, or on a weekend or holiday, count as received the next business day.
- Paper claims are judged on the contractor receipt date, not the postmark.
The distance between sent and received is where real money disappears. A claim that fails a front-end edit and comes back unprocessable was never filed, in Medicare’s reading, however many times the clearinghouse transmitted it. The clock keeps running while the claim bounces, and the rejection notice is the only warning you get.
Where the limits actually live, payer by payer
There is no national standard. The number comes from a regulation, a state manual, a contract or a state insurance law, and often from more than one of them at once. The table below shows the spread using published rules.
| Payer or program | Published limit | What starts the clock |
|---|---|---|
| Medicare fee-for-service | 12 months | Date of service; Through date for institutional claims |
| Medicare Advantage plan | Plan provider manual; one Blue MA plan publishes 365 days | Date of service or discharge |
| Texas Medicaid | 95 days | Date of service; discharge date for inpatient claims |
| California Medi-Cal | Six months following the month of service | Month of service |
| Commercial plan in New York | 120 days under Aetna’s state supplement | Date of service |
| Commercial plan, other states | Contract and state insurance law | Date of service, or the primary payer’s EOB for secondary claims |
Two rows deserve a closer look, because they show how state law reshapes a national payer’s rule. Aetna’s provider manual supplement for New York requires initial claims within 120 days of the service date, lets the plan reduce payment by up to 25 percent when it reconsiders a late claim, and closes reconsideration entirely for claims submitted 365 days after the service. The same company’s rule in another state can differ, so the matrix belongs to your contracts and your state bulletins, not to an article.
Medicare Advantage is the row that catches billing teams most often. The federal 12-month limit applies to Original Medicare claims processed by a MAC. A Medicare Advantage plan runs its own claims operation under its own provider manual, and its window can be shorter or longer than a year. The Kansas Preferred Blue Medicare Advantage manual, for example, sets 365 days from the date of service or discharge. Read the document for the plan on the member’s card.
A published limit changes with a contract amendment, a state bulletin or a manual revision. Record the document name and revision date beside every number in your matrix, and reopen the rows you have not checked in a year.
Build the matrix: one row per payer, plan and claim type
A working matrix is smaller than most teams expect and far more specific than a list of payer names. One row per payer, per plan or product line, per claim type. A commercial PPO, the same company’s Medicare Advantage product and its Medicaid MCO are three rows, because they answer to three different rulebooks.
Use the product name from the eligibility response, not the parent company’s brand.
Original, corrected, secondary or appeal. Each has its own deadline and its own start event.
Days or months, and whether the clock begins at the service date, the discharge date or the primary payer’s EOB date.
Manual name, section, revision date and the page you read. A number without a citation is a guess with a deadline attached.
One person accountable for keeping the row current, usually the revenue cycle lead, with new plans handed to whoever manages credentialing.
Work to 75 percent of the payer’s window so a rejection still leaves time to correct and refile.
The internal deadline is what makes the matrix operational. A 90-day payer limit with a 67-day internal target leaves three weeks to absorb a clearinghouse rejection, a missing modifier or a records request. Without that buffer, the first rejection is also the last chance.
This is also the first thing a competent denial management process fixes, because the losses it prevents never reach an appeal queue.
Corrected claims, secondary claims and appeals run on different clocks
Billing teams lose money when they treat every resubmission as the same event. A corrected claim replaces a claim the payer already adjudicated, and the payer’s policy decides whether the original window still applies or a new one starts at the remittance date. A secondary claim often starts at the primary payer’s explanation of benefits. An appeal starts at the denial notice.
- Corrected claim: resubmitted with the frequency code that marks it as a replacement, so the payer does not read it as a duplicate.
- Secondary claim: the primary payer’s EOB date is the start event with many payers, so the deadline is later than the service date suggests.
- Appeal or reconsideration: the denial notice sets the clock, and that window is usually much shorter than the filing window.
Medicare’s appeal clock is 120 days from receipt of the initial determination, and the notice is presumed received five days after its date. That 120 days is not a filing extension. If the original claim missed the 12-month limit, a redetermination request will be dismissed, because a late-filing denial is not an initial determination.
Medicare’s claims processing manual states that a determination that a claim was not filed timely is not subject to appeal. A reopening request under the CMS exceptions in manual section 70.7 is the only path, and it requires documentation of the specific exception.
The exceptions that can still save a late claim
Medicare recognizes four exceptions to the 12-month limit, and each requires proof of a specific event. None of them cover a claim that was simply forgotten.
- Administrative error by Medicare, a MAC or another agent acting within its authority. The extension runs through the last day of the sixth calendar month after the month the error was corrected, and requests extending beyond four years from the date of service are not accepted.
- Retroactive Medicare entitlement, where the patient was not entitled to Medicare when the service was furnished and later received notice of entitlement effective on or before that date.
- Retroactive entitlement involving a state Medicaid agency, where Medicaid paid, Medicare entitlement arrived later, and Medicaid recovered its payment six months or more after the service.
- Retroactive disenrollment from a Medicare Advantage plan or a PACE organization, where the plan recouped its payment six months or more after the service.
Medicaid adds a related problem. Federal rules require states to make eligibility effective no later than the third month before the month of application, so a patient who applies in June can be covered for services delivered in March. A practice that wrote off a March balance in April has to reopen the account, confirm the eligibility span, and file inside the state’s own window, which may already have closed.
Documentation decides these requests. For an administrative error you need the agency letter, the claims processing issue log entry, or a written statement from an agency employee with personal knowledge. For retroactive entitlement you need the SSA or Railroad Retirement Board notice, or the MAC’s verification of the entitlement date in the Common Working File.
The same evidence discipline is what separates a clean medical billing services operation from one that spends its month explaining write-offs.
Why a timely filing denial is usually unwinnable
Once a payer denies for timely filing, the burden flips. The practice has to prove the claim arrived inside the window, and the only evidence that survives review is a payer acknowledgment: a clearinghouse acceptance report paired with a payer-generated acceptance, an ERA showing the receipt date, or a portal record with a claim number and a received date. A transmission log showing your file left the building proves nothing about arrival.
When that evidence does not exist, the write-off is the correct outcome. Charging the patient does not fix the balance. Medicare’s manual is explicit that when a provider is responsible for the late filing, the provider may not charge the beneficiary beyond the deductible and coinsurance that would have applied had the claim been paid.
The productive question after a write-off is which process failed. Timely filing losses cluster around a handful of causes: eligibility discovered after the visit, a coordination of benefits order that was wrong on the card, an authorization that was never obtained, a clearinghouse rejection nobody worked, or a clinician who was not credentialed when the service happened. Each cause has a different fix, and a loss log sorted by cause tells you which fix pays first.
For practices running lean, outsourced medical billing services often exist for exactly this reason: the deadline work is daily, and nobody in the office owns it.
A weekly control that keeps the clock visible
- Run an unbilled report every Monday, sorted by date of service rather than charge entry date.
- Age every open claim against its own payer deadline, and flag anything past 50 percent of the window.
- Work clearinghouse rejections within two business days, and log the reason on the claim.
- Verify eligibility and coordination of benefits before the claim goes out, not after it denies.
- Review one payer manual entry each week against the live document, and initial the check.
- Report timely filing write-offs by cause at the monthly close.
The weekly rhythm matters more than the software. A practice that reviews its aging report by date of service finds a 120-day problem at day 45. A practice that reviews by dollar balance finds it at day 121, which is the same day the payer closes the file.
Timely filing questions practice managers ask
It starts at the date of service for nearly every original claim. Medicare uses the From date on a professional claim and the Through date on an institutional claim with a span of dates. Some payers start a fresh window at the remittance date for corrected claims, and many start secondary claims at the primary payer’s EOB date. Billing dates reset nothing.
With Medicare, no. The manual treats a late-filing denial as something other than an initial determination, so it carries no appeal rights. A reopening request under one of the four CMS exceptions is the only route. Commercial payers often accept a reconsideration, but they require proof that the claim arrived on time, such as a payer acknowledgment or an ERA with a receipt date.
Only when the payer’s policy says so. Some payers give a new window measured from the original remittance date, while others require the correction to land inside what remains of the original date-of-service window. Submit corrected claims with the replacement frequency code so the payer does not deny them as duplicates, and record which rule applies in your matrix.
It is whatever the plan’s provider manual says, and it is not the federal 12-month rule. One Blue Cross Medicare Advantage manual sets 365 days from the date of service or discharge, and other plans publish shorter windows. Check the plan document tied to the member’s card instead of assuming a year, and revisit it when the plan revises its manual.
It can move the start date. Many payers measure a secondary claim from the primary payer’s EOB date, which gives more time than the service date suggests, and others still measure from the service date. Confirm the rule in writing before you rely on it, and treat a missing primary EOB as an open task with its own internal deadline.
No. Medicare counts the date the contractor receives a claim that passes its completeness and validity edits. A claim returned as unprocessable was never filed, and the clock kept running while it sat in a rejection queue. Work rejections within two business days so the original window is not consumed by administrative back and forth.
Yes, in some states. Aetna’s provider manual supplement for New York requires initial claims within 120 days of the service date, which reflects state insurance guidance rather than a national corporate rule. When a state sets a minimum filing period, the plan must honor it for members in that state. Check state insurance department bulletins alongside the contract.
The bottom line
The filing limit is not paperwork; it is the single date after which a payer owes you nothing. Write it down before the first claim goes out, work to a deadline three weeks earlier than the payer’s, and keep the proof of arrival for every claim you might one day have to defend. Everything else in denial management is recoverable, and this one is not.
How many claims in your aging report are already past a deadline nobody wrote down?
MedFactor builds the filing matrix, works the unbilled report by date of service, and files the reopenings that still have a route. Send a recent aging report and we will show you which balances are recoverable and which ones are already gone.
Request a free filing deadline auditThis article summarizes published CMS, MAC, state Medicaid and payer rules as of October 2026 and is not legal advice; confirm every deadline in your own contracts and state guidance.
