Can you still get paid for a mental health claim past the timely filing deadline?

What is a timely filing limit, and how long do you actually have?

A timely filing limit is the deadline a payer sets for receiving a claim after the date of service. There is no single number, because it is set payer by payer and, for commercial plans, by your contract with them. Medicare is the one that is fixed in regulation: one calendar year.

The CMS Medicare Claims Processing Manual, Chapter 1 (§70) states that under 42 CFR 424.44, “in general,” such claims “must be filed to the appropriate Medicare claims processing contractor no later than 12 months, or 1 calendar year, after the date the services were furnished.”

One detail in §70.1 is worth knowing precisely, because it is the difference between a claim that is timely and one that is not. The clock starts at the date of service — but for professional claims (the CMS-1500 or 837-P, which is what an outpatient practice files) that carry span dates, CMS uses the line item “From” date. Institutional claims with span dates use the “Through” date instead. Those two rules point in opposite directions, and guidance written for hospitals routinely quotes the wrong one at practices. CMS also notes that if a line item’s “From” date is untimely but its “To” date is timely, contractors split the line and deny the untimely part.

Everything else is shorter, and it varies more than most people expect. Among the state Medicaid programs we checked, the published initial filing deadlines run from 90 days in New York and 95 days in Texas to 365 days in Washington. That is a four-fold spread between three state programs, which is the actual point: there is no industry number, and the ranges that circulate in billing blogs cite each other rather than any payer. We are giving you named examples instead of a range because no neutral authority publishes one.

For the largest commercial payers there is often no published number at all. UnitedHealthcare’s 2026 provider administrative guide answers the question by pointing back at you — its “Timely filing guidelines” entry reads, in full, “Refer to your internal contracting contact or Participation Agreement for timely filing information,” and elsewhere the guide says “Timely filing limits vary based on state requirements and contracts.” That is not evasion; it is the truth of how these deadlines are set. If you do not have the filing and appeal windows for your top five payers written down somewhere, that list is worth an afternoon, and it is the single most reusable thing in this article.

One behavioral-health wrinkle drives more timely-filing denials than most practice owners expect: the carve-out. When mental health benefits are administered by a separate managed behavioral health organization, that plan can have its own filing address, payer ID, and clock — different from the medical plan printed on the same card. A claim sent on time to the wrong entity comes back denied as late. It is worth saying plainly that this is a commercial and Medicaid-managed-care problem: Medicare’s manual does not address carve-outs at all, and §70.2.1 cuts the other way for Medicare, since re-routed claims “are not considered claims under Medicare regulations until received by the appropriate Medicare contractor.”

Can a claim denied for timely filing be appealed?

For Medicare, essentially no — and this is where most articles on this subject, including the earlier version of this one, get it wrong while citing CMS as the authority.

§70.4 of the manual is unambiguous: “When a claim is denied for having been filed after the timely filing period, such denial does not constitute an ‘initial determination’. As such, the determination that a claim was not filed timely is not subject to appeal.” §70.6 draws the line between the beneficiary and you: the beneficiary keeps “the usual appeal rights,” while for a provider or supplier protesting the denial, “no formal channels of appeal are available. However, the contractor may, at the request of the provider or supplier, informally review its initial determination.” An informal review on request is not an appeal, and it is what you have.

There is a second Medicare trap underneath that one, and it lands squarely on outpatient mental health. Under 42 CFR 405.906, the parties to an initial determination include “a supplier who has accepted assignment” for the items or services at issue. A psychologist, clinical social worker, or psychiatrist in private practice is a supplier in Medicare’s vocabulary, not a “provider of services” — so party status, and the appeal rights that come with it, turn on whether assignment was accepted. A non-assigned supplier has to obtain an assignment of appeal rights from the beneficiary before it can act at all.

For commercial plans and Medicaid managed care the answer is different, because the rules are contractual rather than statutory. Those payers generally do publish a reconsideration or appeal path for filing denials, and it turns on documentation rather than judgment. In the federal reporting taxonomy, untimely claims sit in the administrative bucket alongside duplicates and missing information — a category distinct from medical necessity, and one that accounted for 25% of reported in-network denial reasons in 2024 (KFF’s reading of the same data; note that is a share of denial reasons, not of claims). An administrative denial is a fact you document, not a judgment you re-argue.

What we are not going to tell you is how often that succeeds. There is no public figure for the rate at which timely-filing denials are overturned, for any payer type, and the reason is structural rather than accidental. In the CMS Transparency in Coverage file that both figures come from, the published field definitions put “Untimely Claim Filing” inside a single plan-level count that lumps it with eight other administrative reasons, while the appeals-overturned counts are issuer-level and carry no reason dimension at all. The two cannot be joined, because the column that would join them does not exist. Any overturn rate you see quoted for timely filing specifically is somebody’s marketing — including when the somebody is a billing company.

Whatever the payer, move on it — but do not assume the appeal clock is the short one. It is a separate clock set by the plan, and it is not reliably shorter than the filing window. Aetna gives 180 calendar days to file a reconsideration (and 60 more to appeal that decision), and Cigna says its single-level payment review must “in general” be initiated within 180 calendar days (on a policy page dated April 2021, and subject to applicable law and the provider agreement); Texas Medicaid allows 120 days to appeal against a 95-day filing deadline — longer than the window to file in the first place — and UnitedHealthcare’s guide gives you 12 months: “You must submit your reconsideration and appeal to us within 12 months from the date of the original claim EOB or PRA (or as required by law or your Agreement).” That parenthetical is doing real work — the same guide notes claim reconsideration does not apply in some states — and it is the point: look the number up in your own agreement rather than working from a rule of thumb. Guessing short wastes claims you had time to work, and guessing long loses them outright.

One distinction worth keeping straight, because the two get conflated and they are not the same right. A practice appealing in its own name is exercising a contract right under its participation agreement — that is what the Aetna, Cigna and UnitedHealthcare windows above are. The separate 180-day right under the federal ERISA claims rule belongs to the claimant, and that is a defined term: 29 CFR 2560.503-1 sets minimum requirements for plan procedures “pertaining to claims for benefits by participants and beneficiaries (hereinafter referred to as claimants),” requires group health plans to give claimants “at least 180 days following receipt of a notification of an adverse benefit determination within which to appeal,” and provides that the procedures “do not preclude an authorized representative of a claimant from acting on behalf of such claimant.” That rule reaches ERISA-covered employer plans — not individual-market coverage, including non-group Marketplace plans, and not government or church plans. Employer coverage bought through the SHOP Marketplace is group coverage and is generally covered. A practice reaches the right only as the member’s authorised representative, usually with a signed designation. Same number in some cases, different basis, different paperwork.

What counts as a valid timely-filing exception?

Two different questions live under that heading, and blurring them is how practices build appeals that were never going to work. Medicare’s exceptions are enumerated in regulation and are narrow. Commercial exceptions are whatever your contract says they are.

Medicare. §70.7 allows exactly four exceptions to the one-year limit, and there is no general good-cause or hardship provision anywhere in §70:

• Administrative error— where the failure to meet the deadline “was caused by error or misrepresentation of an employee, Medicare contractor, or agent of the Department that was performing Medicare functions and acting within the scope of its authority.” Both qualifying clauses matter: it is Medicare’s own error, not your clearinghouse’s and not a commercial payer’s. §70.7.1 also requires “a clear and direct relationship between the administrative error and the late filing.”
• Retroactive Medicare entitlement — the beneficiary was not entitled when you rendered the service and is notified afterwards of entitlement backdated to or before that date.
• Retroactive entitlement involving a State Medicaid agency — the same situation where the state then recoups its payment from you six months or more after the service.
• Retroactive disenrollment from a Medicare Advantage plan or PACE organization — again where the plan recoups six months or more after the service.

Read that list against the things practices usually want to argue. Retroactive eligibility is on it. Proof that you filed on time and the payer lost the claim is not. Clearinghouse or payer system error is not. A coordination-of-benefits delay is not. Sending the claim to the wrong payer entity is not — and for that last one §70.2.1 is actively adverse. None of those is a Medicare exception, however reasonable it sounds.

Commercial and Medicaid managed care. Here the same list usually does work, which is exactly why the two must not be conflated. The payers we checked — UnitedHealthcare, Aetna and Cigna — each publish a reconsideration path, and the categories that recur across plans are proof of timely submission, payer or clearinghouse error, retroactive eligibility, coordination-of-benefits delay where the primary had to determine first, and carve-out or payer-ID misrouting. We are deliberately not attaching a source to that list as a general rule, because it is a composite of individual payer policies rather than a published standard. Pull the exception language from the specific plan’s provider manual before you build the appeal; it is the standard you will be held to, and it varies more than you would expect.

How do you prove a claim was filed on time?

With a paper trail showing the payer received the claim by the deadline. The strongest evidence is an electronic acceptance report — the clearinghouse or payer acknowledgment confirming receipt — not your internal note that you sent it.

Payers are unusually specific about what they will accept. UnitedHealthcare’s 2026 administrative guide says proof must include “the date the claim was submitted to us or another payer,” “the date the claim was accepted by us or another payer,” member identification, date of service, and provider identification — and that on a timely-filing denial “the reconsideration process offers the opportunity to submit proof that this was outside of your control.” In practice that means keeping clearinghouse acceptance and 277CA reports, payer acknowledgments (999 and 277), and the remits on related claims, plus submission logs and delivery receipts for anything filed on paper.

The distinction that trips practices up is the one between a rejected claim and an accepted one, and the same guide states it flatly: “UnitedHealthcare claims that are rejected are not proof of timely filing as rejections require further action from the provider before the claim can be adjudicated.” A claim that bounced at the clearinghouse was never received, and the filing clock kept running the entire time it sat in a queue somebody assumed was a submission. Reconciling rejections within days rather than weeks is what preserves the timely-filing argument later — and it is the same discipline that prevents the denial in the first place.

Does mental health parity (MHPAEA) help with a filing denial?

No — and it is worth being precise about why, because parity gets invoked for behavioral health denials of every kind and this is one where it does not reach.

Parity governs how restrictive mental health and substance use benefits may be relative to medical and surgical ones. The regulation at 29 CFR 2590.712 defines the relevant term this way: “Treatment limitations include limits on benefits based on the frequency of treatment, number of visits, days of coverage, days in a waiting period, or other similar limits on the scope or duration of treatment.” A claim-filing deadline is a condition on payment, not a limit on the scope or duration of treatment. The regulation’s list of non-quantitative treatment limitations — prior authorization, step therapy, formulary design, network composition and the rest — contains nothing about filing windows, and the phrases “timely filing,” “filing deadline,” and “filing limit” do not appear anywhere in the regulation at all.

One variant is genuinely untested, and we will not pretend otherwise: a carve-out that imposes a shorter filing deadline on behavioral health claims than the medical plan applies to medical ones. The non-quantitative list is expressly illustrative rather than exhaustive, so an argument exists in principle — but no agency guidance or decision we could find has tested it. Treat it as an open question, not a strategy.

The current state of the rules is also worth stating plainly, because it changed and much of what is written about it online has not kept up. On May 15, 2025 the Departments of Labor, Health and Human Services, and the Treasury announced that they “will not enforce the 2024 Final Rule or otherwise pursue enforcement actions, based on a failure to comply that occurs prior to a final decision in the litigation, plus an additional 18 months.” That relief “applies only with respect to those portions of the 2024 Final Rule that are new in relation to the 2013 final rule,” and the Departments note that “MHPAEA’s statutory obligations, as amended by the CAA, 2021, continue to have effect.” As of August 22, 2026 that statement has not been withdrawn or superseded and no replacement rule has been published — but the pause is tied to litigation we are not tracking day to day, so check its current status before relying on it. The statute itself, including the comparative-analysis requirement, applies either way. None of that changes the answer above: for a filing denial, your levers are the payer’s own exception process and your contract, not parity.

Which past-deadline claims are actually worth working?

Fewer than the aging report suggests, and the honest sort is by remaining window and by what the claim turns on — not by age or by dollar value.

The reason the pile exists at all is that rework loses to new work every time the day is full. The AHIMA Journal reports the industry average that as many as 60% of returned claims are never resubmitted, and puts the cost of reworking a denied claim at an average of $25 per claim for practices. Both numbers need their labels. The 60% is a ceiling rather than a range, it covers what the source calls returned claims rather than every denial — AHIMA does not define the term — and it is an industry average the journal repeats from 2017–2019 trade reporting rather than a study it conducted. The $25 is the practice figure; the $181 quoted beside it in the same sentence is the hospital figure, and treating the two as the ends of one range — as this article and four others on this site previously did — overstates what rework costs a practice by roughly seven times. Neither number is behavioral-health specific, and neither sizes your pile.

Now the part that argues against working old claims at all, which you should have before you decide. In KFF’s analysis of 2024 HealthCare.gov data, insurers denied about 19% of in-network claims, ranging from 3% to 36% across insurers. Two scope facts change what that means. First, it is a final-adjudication rate: KFF states that “claims that were initially denied, then subsequently resubmitted and paid, are not included as denied claims in the denial rate” — so it leans towards denials that stuck, which is the population this article is about. Do not read it as a clean measure of permanent loss, though: KFF cautions that where a new claim is filed instead of resubmitting the original, the original still counts as denied even if the new one was paid, and that claims initially denied and later paid cannot be identified in the data at all. Second, when consumers did appeal, insurers upheld 66% of appeals. Most consumer appeals fail.

Be careful with that KFF data in one specific way, because it is routinely misused in exactly the direction that would flatter us. KFF also reports that consumers appealed fewer than 1% of denied claims — but that figure is about consumers, not about billers or practices. KFF reports nothing at all about provider-initiated appeals. Anyone telling you “99% of denials go unchallenged, so imagine what is sitting in your A/R” is transferring a patient-behaviour statistic onto a professional workflow it never measured. The KFF scope is also narrower than it looks: HealthCare.gov qualified health plans only, including state-based Marketplaces that run on HealthCare.gov but excluding those on their own platforms and excluding all group plans. And the only behavioral-health split in the current data sits inside medical-necessity denials, which the CMS public use file reports for plan years 2018–2024 with plan-level submission required from plan year 2020; insurers do not report whether claims received and denied overall were behavioral health until plan-year 2027 certification. So the 19% is not a mental-health number, and no clean federal behavioral-health denial rate exists yet.

So the triage is unglamorous. Work the claims where the window is still open and the argument is documentary, start with the payer whose deadline falls first, and group by payer before you start, because one routing or enrollment problem usually explains a whole cluster at once. Past-deadline Medicare claims with no §70.7 exception are gone; write them off and spend the hour on the ones that are not. The wider version of this triage, across everything in an aging report rather than just filing denials, is in the guide to recovering aged A/R, and what a normal denial rate and days-in-A/R actually look like is in the benchmarks guide.

Key takeaways

• For Medicare, a timely-filing denial is not appealable at all — CMS says it is not an initial determination, and a provider gets only an informal contractor review on request.
• Medicare allows exactly four exceptions, all narrow: administrative error by “an employee, Medicare contractor, or agent of the Department” acting within the scope of its authority, and three flavours of retroactive entitlement or disenrollment. There is no good-cause or hardship exception.
• Proof of timely filing, clearinghouse error, COB delay and payer misrouting are not Medicare exceptions — but they are usually the ones commercial and Medicaid managed-care plans do accept. The authority is that plan’s provider manual, not a rule of thumb.
• Medicare’s clock starts at the date of service, and for professional claims with span dates it is the line item “From” date — not the “Through” date that hospital-oriented guidance quotes.
• Do not assume the appeal clock is shorter than the filing clock. Texas Medicaid gives 120 days to appeal against 95 to file, and UnitedHealthcare gives 12 months. Look your payers’ numbers up.
• A rejected claim is not an accepted claim. The filing clock keeps running while it sits, so reconciling rejections in days rather than weeks is what preserves the argument later.
• Behavioral health carve-outs cause “filed on time, to the wrong entity” denials — check the behavioral plan’s filing rules separately from the medical plan’s.
• Parity (MHPAEA) is not a lever here: the regulation defines treatment limitations in terms of the scope and duration of treatment and never mentions filing deadlines. A carve-out with a shorter deadline than the medical plan is an untested question, not a strategy.
• Nobody publishes how often timely-filing denials get overturned. Treat any quoted success rate as marketing.