A denial notice is not a verdict. It is a document that starts a clock, and the clock is the only part of it that cannot be renegotiated later. What the published outcome data show is a system where reversal is common among the people who ask and asking is uncommon, which is a different problem from the one most readers expect. What is being decided in the first place is described in the prior-authorization article.
Two ladders, depending on who pays
Private coverage runs on two rungs. A group health plan must give a claimant at least 180 days after receiving notice of an adverse determination in which to appeal it, and must provide a review that gives no deference to the original decision and is conducted by someone other than the person who made it, or that person’s subordinate.[1] After that internal appeal is exhausted, an independent external review is available.
Medicare Part D runs on five. A coverage determination by the plan is followed, in order, by a redetermination by the same plan, a reconsideration by an independent review entity under contract to CMS, a hearing before an administrative law judge or attorney adjudicator where the amount in controversy is met, review by the Medicare Appeals Council, and judicial review where a higher amount in controversy is met.[3] The rules governing what Medicare will consider in the first place are in the public-coverage article.
The deadlines that actually bind
Three windows do most of the damage when they are missed. For a Part D drug, a request for redetermination must be filed within 60 calendar days after receipt of the written coverage determination notice, and the plan then has no later than seven calendar days to decide a standard request or 72 hours to decide an expedited one.[3]
For an external review of a private plan’s final internal denial, the request must be filed within four months of receiving the notice. The plan then has five business days to complete a preliminary eligibility review, and the independent review organization must issue its written decision within no more than 45 days of receiving the request.[2]
Two details in that regulation are worth knowing because they remove common reasons for not filing. A state external review process may not impose any minimum dollar threshold for a claim to be eligible, so a $500 minimum is specifically prohibited. Any filing fee must be nominal, capped at $25 per request with an annual limit of $75, refunded if the determination is reversed and waived where paying it would impose undue financial hardship.[2]
Where the claim involves urgent care, both the original determination and the determination on review must be made no later than 72 hours after receipt, and the plan must defer to the attending provider’s judgment that the claim is urgent.[1][2]
The overturn rates, and who they describe
Medicare Advantage publishes the fullest record. Insurers received nearly 53 million prior authorization requests in 2024 and fully or partially denied 4.1 million of them, a rate of 7.7%. Of those denials, 11.5% were appealed, and of the appeals, 80.7% were partially or fully overturned.[4] Across every year in that analysis, more than eight in ten appeals reversed the initial denial.
Marketplace coverage shows the same asymmetry with weaker odds. Of roughly 85 million denied in-network claims in 2024 — a 19% average denial rate, ranging from 3% to 36% across insurers — at least 262,982 were appealed, under 1% of the total. Insurers upheld 165,863 of those, about 66%, and overturned roughly 34%. At least 5,881 went on to external review, about 4% of the internal appeals that were upheld.[5]
Traditional Medicare complicates the picture in the other direction. It subjects far fewer services to prior authorization, but denied 22.9% of the requests it did review in 2024, a substantially higher share than Medicare Advantage’s 7.7%.[4] A low denial rate and a permissive program are not the same thing.
Why the reversals stop after the first rung
The 80.7% is the plan overturning itself. It is not what happens once an outside body reviews the same file. An analysis of independent review entity determinations from January 2020 to December 2024 found that across all healthcare services, only 4.5% of appeals reaching that stage were decided favorably or partially favorably for the enrollee.[7]
A separate analysis of the same public CMS appeals data for 2022 through June 2024 found inappropriate denials in 4.66% of all health service appeals, against 17.39% for radiation therapy specifically, with the gap significant in every year examined.[8] Neither study concerns this drug class, and both are cited for the structure rather than the subject: the second level is a different proposition from the first, and most of what is reversed is reversed by the plan that issued the denial.
The most common denial rationale recorded in the first of those analyses was inadequate documentation.[7] That is consistent with the first-rung reversal rate, and it is the part of the process a prescriber’s office rather than a patient is positioned to fix.
The reason most denials are never appealed
The 2025 AMA prior authorization physician survey — a 44-question web-based instrument administered in December 2025 to 1,000 practicing physicians drawn from a Medscape panel, 40% primary care and 60% specialists, all screened to provide at least 20 hours of patient care a week — asked directly. Just 1 in 5 (21%) report that they always appeal an adverse decision.[6]
The stated reasons, in order: 59% do not believe the appeal will be successful based on past experience, 52% report insufficient practice staff resources or time, and 49% report that patient care cannot wait for the health plan to approve the request.[6]
The first of those is the one the administrative data contradict most directly, at least at the first level. The second and third are not beliefs at all; they are constraints, and no published overturn rate addresses them. A process that reverses four denials in five while being used by one denial in nine is not working as its outcome statistics suggest.
A missed deadline is not a dead file
The Part D rules contain a provision that runs the other way from most of this. If a plan sponsor fails to issue a redetermination within the applicable timeframe, that failure itself constitutes an adverse redetermination decision, and the sponsor must forward the request to the independent review entity within 24 hours of the deadline expiring.[3] A plan that does not answer does not thereby keep the file; it loses the next decision to an outside body automatically.
External review carries a matching provision on the other end. A plan or issuer must provide benefits under a final external review decision without delay, including by making payment on the claim, regardless of whether it intends to seek judicial review, unless and until a court decides otherwise.[2] Upon receiving a reversal, the plan must immediately authorize the care or pay the benefit.
What a denial notice has to say
The notice itself is regulated, which matters because its contents determine what an appeal can be built from. A Part D reconsideration notice must state the specific reasons for the decision in understandable language and, where adverse, inform the enrollee of the right to a hearing where the amount in controversy threshold is met and describe the procedures for obtaining one.[3] On the private side, a plan must treat even a rescission of coverage as an adverse benefit determination subject to the full appeal machinery, whether or not it affects a particular benefit at the time.[2]
What the amount in controversy is doing
The Medicare ladder has a floor written into it. To reach an administrative law judge, the amount remaining in controversy must be at least $100 as adjusted upward by the medical care component of the Consumer Price Index measured from July 2003, rounded to the nearest $10. Judicial review requires $1,000 on the same adjusted basis, and the Secretary publishes the current figures in the Federal Register.[3]
For a drug appeal the amount is computed as the projected value of the benefit, including any costs the enrollee could incur across the refills prescribed during the plan year, reduced by cost sharing.[3] A monthly medication in this class generally clears the lower threshold comfortably, which is one of the few places where an expensive drug improves a patient’s procedural position rather than worsening it. What a year of it costs is worked out in the annual-cost article.
What a cash purchase has instead
Outside a benefit there is no denial, because there is no claim, and therefore no internal appeal, no external review, no independent review organization and no reversal. The protections above are attached to coverage rather than to the patient, and they do not follow a person into a subscription. What governs there is a contract, and the terms that matter are cancellation and refund terms, which are examined in the refund-terms article.
That route also generally supplies a different product: most of the cash market dispenses compounded preparations, which are not FDA-approved and are not reviewed by the FDA for safety, effectiveness or quality before dispensing. What each seller publishes is recorded in the seller write-ups, and established the way the methodology describes.
What this page cannot tell you
Nothing above is advice about a particular denial, and no appeal described here carries any predictable outcome. The deadlines quoted are federal minimums and maximums; an individual plan may allow longer to file, a state external review process may add requirements, and a self-funded plan, a marketplace plan and a Part D plan run on three different ladders for the same prescription.
The documents that actually govern are the denial notice itself, which federal rules require to state the specific reasons in understandable language and to describe the procedures for the next step, and the plan’s own appeal procedures. Who wrote the criteria the denial applied is a separate question, answered in the employer article.