How to appeal a Medicare prior authorization denial: 5 steps that win more than 8 out of 10 times

Short answer

You have 60 days from the date on your Medicare Advantage denial notice to file a Level 1 appeal, called a reconsideration. For Original Medicare’s few prior authorization programs, resubmission with corrected documentation restarts the process. More than 8 in 10 appeals that reach a decision are overturned in the patient’s favor (Kaiser Family Foundation, 2024 data). If waiting could seriously harm your health, request an expedited appeal — the plan must decide within 72 hours.

Common reasons prior authorizations get denied

Most Medicare prior authorization denials fall into one of six patterns. Knowing which one applies to you shapes the appeal:

• Missing or incomplete clinical documentation. The plan says your doctor did not submit enough evidence to show the service is medically necessary. This is the most common reason — and the easiest to fix on appeal.
• The service does not meet the plan’s medical necessity criteria. The documentation is complete, but the plan’s clinical rules say the service is not warranted for your specific diagnosis or history. This is where clinical guidelines, specialist letters, and peer-reviewed studies matter most — and your treating physician or specialist typically supplies those references when they apply.
• Wrong billing code. The provider used a CPT or HCPCS code the plan does not accept for this indication. Corrected coding and resubmission usually resolves it without a formal appeal.
• Formulary exclusion (Part D). The prescription is not on your Part D plan’s approved drug list. The path is a formulary exception, not a standard prior authorization appeal. Part D formulary exception requests are often denied when the prescriber’s supporting statement lacks enough clinical detail — a stronger clinician-authored statement is frequently what turns the appeal around.
• Out-of-network provider. Your Medicare Advantage plan requires an in-network provider for this service and you used an out-of-network one. Some plans allow exceptions for specialty care not available in-network.
• Wrong plan or coverage confusion. The service is covered under Part B but was submitted to Part D, or vice versa. Fixing the routing fixes the denial without an appeal.

Read your denial letter carefully. Federal rules require Medicare Advantage plans to state the specific reason for every denial — vague “not medically necessary” wording is no longer allowed as of January 2026. If your letter is unclear, call the number on it and ask.

The 82% statistic: why appealing is worth your time

Every year since 2019, Kaiser Family Foundation has analyzed Medicare Advantage prior authorization data reported to the Centers for Medicare & Medicaid Services. The pattern is consistent and striking.

In 2024, Medicare Advantage insurers made about 53 million prior authorization determinations. They fully or partially denied 4.1 million of them — a 7.7% denial rate. Of those denials, patients or providers appealed only 11.5%. But of those appeals, more than 80% were fully or partially overturned.

The American Medical Association has cited similar overturn rates — approximately 82% — in its own 2024 Prior Authorization Physician Survey. Every year, without exception, appealed denials are reversed far more often than they are upheld.

Why? The most common reason is that the plan’s initial reviewer did not have the full picture. When your doctor submits additional documentation, cites clinical guidelines, or explains why standard criteria do not apply to your specific situation, plans overturn the denial. The appeal is not adversarial — it is a documented case for the same service that was requested the first time.

The takeaway is simple. If you receive a denial, appeal it.

Before you appeal: try peer-to-peer review first

Before you file a formal appeal, ask your treating physician’s office to request a peer-to-peer review. Peer-to-peer requests are initiated by the treating provider’s office — not by the patient directly — and are a phone call between your doctor and the plan’s medical director. It is not an appeal in the technical sense; it is a clinical conversation.

Peer-to-peer often resolves the denial in days, not weeks. Your doctor explains the clinical rationale, answers questions, and clarifies any documentation gap. If the medical director agrees, the plan approves the service without a formal appeal being filed.

Two important timing points:

• Plan-specific deadlines apply. Many Medicare Advantage plans set a specific window for requesting peer-to-peer before the formal appeal clock starts. Check your denial letter or call the plan to confirm the exact deadline for your plan.
• Peer-to-peer does not extend the appeal deadline. The 60-day window to file a formal Level 1 appeal keeps running regardless of whether peer-to-peer is in progress. Track both timelines in parallel.

Not every plan offers peer-to-peer for every denial, and not every specialty is covered. Ask your doctor’s office to check. Even if peer-to-peer does not overturn the denial, it often surfaces exactly what additional documentation the plan wants — which strengthens the formal appeal you file next.

Step-by-step: how to file a Medicare prior authorization appeal

The formal appeal process has five steps. Most appeals succeed at step 1 or step 2 — you should not need to go further unless the denial involves a large dollar amount or a complex clinical dispute.

1. Read your denial letter carefully. Note the exact denial reason, the plan’s denial code, the deadline to appeal, and the address or portal for filing. Medicare Advantage denials give you 60 days from the notice date to file a Level 1 appeal.

2. Gather your evidence. This is the single most important step. Your appeal is only as strong as the documentation behind it. Assemble:

   • Your medical records relevant to the denied service
   • A letter of medical necessity from your treating physician
   • Any specialist letters or second-opinion notes
   • Documentation of failed alternatives, if the plan wants you to try something else first
   • Clinical practice guidelines and peer-reviewed studies where these apply — your treating physician or specialist typically supplies these references. You are not expected to locate published medical literature yourself.

   Not every appeal requires published clinical guidelines or journal articles. Many successful appeals rely primarily on a strong letter of medical necessity from your treating physician combined with your medical records. Guidelines and studies help when the denial hinges on medical necessity criteria — they are optional evidence, not required paperwork.

3. Write your appeal letter. Keep it short, factual, and organized. A one-page letter with clear attachments works better than a long letter without evidence. See the sample template below.

4. File within the deadline. For Medicare Advantage, submit within 60 days of the denial notice through your plan’s appeals portal, fax, or mail address. For Part D redeterminations, the deadline is also 60 days. For Original Medicare’s few prior authorization programs (WISeR pilot states, certain hospital outpatient services, durable medical equipment), submit resubmission through your provider — Original Medicare uses a different structure.

5. Escalate if denied. If your Level 1 appeal is denied, you have the right to escalate to Level 2 (Independent Review Entity), then Level 3 (Administrative Law Judge hearing), then Level 4 (Medicare Appeals Council), and finally Level 5 (Federal District Court). See the appeals ladder section below for deadlines and thresholds.

Under Medicare Advantage reconsideration rules (42 CFR 422.590), plans must decide standard pre-service reconsiderations within 30 days and expedited reconsiderations within 72 hours. The federal CMS-0057-F rule, effective January 1, 2026, additionally sped up the initial prior authorization decision (before appeal) to 7 calendar days standard and 72 hours expedited — that faster timeline applies to the plan’s first decision, not to the appeal that follows a denial.

Keep a communication log

From the moment a denial enters the picture, keep dated records of every phone call, letter, portal message, and voicemail — including the name of the representative you spoke to, the reference or case number, and what was said or promised. Save copies of everything you submit and every response you receive. If a case moves through multiple appeal levels, that log is often the difference between a decision that hinges on your word and one that hinges on documented facts.

Sample appeal letter template

You can adapt this template to your specific denial. Fill in the bracketed information and attach your supporting documentation.

[Your Name] [Your Address] [Medicare ID or Plan Member ID] [Date]

[Plan Name — Appeals Department] [Plan Address]

Subject: Appeal of Prior Authorization Denial — Reference #[Denial Reference Number], Date of Denial [MM/DD/YYYY]

To the Appeals Reviewer,

I am writing to appeal the denial of prior authorization for [service name, procedure code, or medication name] dated [date of denial notice]. I respectfully request that the plan reconsider this denial and approve the requested service.

Patient information

• Name: [Your Name]
• Date of birth: [DOB]
• Medicare/Plan ID: [ID number]
• Treating physician: [Physician name, NPI if known]

Statement of medical necessity

My treating physician has determined that [service name] is medically necessary for the treatment of [diagnosis and ICD-10 code if known]. The clinical rationale is as follows: [1–3 sentences summarizing why this service is medically necessary for your specific situation — your physician can help you draft this].

Supporting documentation attached

1. Letter of medical necessity from [Physician name], dated [date]
2. Relevant medical records from [date range]
3. [If applicable] Clinical practice guidelines: [specialty society + guideline title]
4. [If applicable] Peer-reviewed studies: [1–3 citations]
5. [Any other relevant documentation — specialist letters, records of failed alternative treatments, etc.]

Requested action

I respectfully request that the plan reverse the denial and approve prior authorization for [service name] so that treatment can proceed without further delay.

If additional information is needed, please contact me at [phone] or my treating physician at [physician phone]. If a decision cannot be reached within the standard timeline, or if delay would seriously jeopardize my health, I request an expedited review with a 72-hour decision timeline.

Sincerely,

[Your signature] [Your printed name] [Date]

Keep a copy of everything you send, and note the date and method of transmission. If you fax or mail the letter, request confirmation of receipt.

The 5 levels of Medicare appeals: what happens after Level 1

If your Level 1 appeal is denied, you have the right to escalate through four more levels. Most patients never need to go past Level 2.

• Level 1 — Reconsideration by the plan (Medicare Advantage) or Redetermination by a Medicare contractor (Original Medicare and Part D). Deadline: 60 days from denial notice. Decision within 30 days (standard pre-service) or 72 hours (expedited) under 42 CFR 422.590.
• Level 2 — Independent Review Entity. External contractor reviews the plan’s decision. For Medicare Advantage, if the plan upholds the denial at Level 1, the case is automatically forwarded to the Independent Review Entity — you do not file a separate Level 2 request. For Original Medicare and Part D, you have 60 days from the Level 1 denial to file. Decision within 30 days (standard) or 72 hours (expedited).
• Level 3 — Administrative Law Judge (ALJ) hearing. Independent judge hears your case. Minimum amount in dispute is $200 as of 2026. Deadline to file: 60 days from Level 2 decision.
• Level 4 — Medicare Appeals Council review. Higher administrative review of the ALJ decision. Deadline to file: 60 days from Level 3 decision.
• Level 5 — Federal District Court. Judicial review of the Council’s decision. Minimum amount in dispute is $1,960 as of 2026. Deadline to file: 60 days from Level 4 decision.

At Levels 1 and 2 you can represent yourself. Levels 3 and above are where some patients hire a Medicare-experienced attorney or a patient advocate to help.

Expedited appeals: when delay could hurt you

If waiting for a standard decision could seriously jeopardize your health, life, or ability to regain maximum function, request an expedited appeal. The plan must decide within 72 hours — not 30 days.

Who can request an expedited appeal: you, your authorized representative (a family member, caregiver, patient advocate, or attorney you have designated), or your treating physician. Any of the three can ask the plan for expedited review. To qualify for expedited status, the treating physician typically provides a written attestation that the standard timeline could harm you — the medical statement is the physician’s job, but the request itself can come from you or your representative.

The physician’s letter should be specific: the diagnosis, the risk of delay, and why the requested service is time-sensitive. Plans cannot deny expedited status without a valid reason, and if they do, that itself is appealable.

Expedited review applies at every level of the appeal ladder, not just Level 1. If your Level 1 expedited appeal is denied, you can request expedited Level 2 as well.

What’s changing in 2026: CMS-0057-F and the WISeR pilot

Two federal changes took effect in January 2026 that directly affect prior authorization and appeals.

CMS-0057-F (Interoperability and Prior Authorization Final Rule). As of January 1, 2026, Medicare Advantage plans, state Medicaid programs, CHIP, and Qualified Health Plans on the federal exchanges must decide initial standard prior authorization requests within 7 calendar days (down from 14) and expedited requests within 72 hours. Every denial must include a specific reason, not vague language. Additional interoperability and data-sharing API requirements take effect January 1, 2027. Part D prescription drug prior authorization is not covered by CMS-0057-F — Part D uses separate timelines (72 hours standard, 24 hours expedited).

Note the CMS-0057-F change applies to the plan’s first decision on a prior authorization request, not to appeals that follow a denial. Appeals of denials continue to follow the Medicare Advantage reconsideration timelines (30 days standard pre-service, 72 hours expedited) under 42 CFR 422.590.

WISeR Model (Wasteful and Inappropriate Service Reduction). As of January 1, 2026, Original Medicare requires prior authorization for a defined list of outpatient services in six pilot states — Arizona, New Jersey, Ohio, Oklahoma, Texas, and Washington — for the first time in decades. Contractors use artificial intelligence and clinician review to decide requests. Deep brain stimulation and percutaneous image-guided lumbar decompression were initially proposed but delayed by CMS; the agency updates the list over time. Providers can resubmit unlimited times and request peer-to-peer clinical review; formal Medicare appeal rights kick in at the claim stage. The pilot runs through December 31, 2031. Emergency care, inpatient services, and beneficiaries in Medicare Advantage, VA, or Indian Health Service are excluded from WISeR.

If your denial happens on or after January 2026, the faster CMS-0057-F timelines apply automatically to the initial Medicare Advantage prior authorization decision. If you have Original Medicare and live in one of the six WISeR states, some outpatient procedures now go through an approval step they did not before.

Part D prescription drug denials

Part D denials follow a different structure. If your Part D plan denies coverage for a drug, your prescriber can request one of three exceptions:

• Formulary exception — the drug is not on the plan’s list at all, and your prescriber attests it is medically necessary.
• Tiering exception — the drug is on the formulary but at a higher cost tier than a comparable alternative.
• Coverage determination for prior authorization — the drug is on the formulary but requires prior authorization review.

Standard coverage determinations must be decided within 72 hours. Expedited requests, for cases where waiting would seriously jeopardize your health, must be decided within 24 hours. If the plan denies the coverage determination, you can appeal — Level 1 is a redetermination, decided within 7 days (standard) or 72 hours (expedited).

How Baba helps

A Baba advocate handles Medicare prior authorization appeals every day. Medicare may cover qualifying patient advocacy or care navigation services — talk to Baba to find out if you qualify. What that looks like in practice for a denial:

• Denial letter review. Your advocate reads your denial letter, identifies the specific reason and code, and explains what the plan is asking for.
• Evidence gathering. Your advocate helps assemble medical records and coordinates with your treating physician on the letter of medical necessity. Where clinical guidelines or peer-reviewed studies apply, your advocate helps your physician’s office identify the right sources — you do not need to hunt through medical journals.
• Appeal letter drafting. Your advocate drafts the appeal letter using your medical facts, and works with your treating physician on the letter of medical necessity.
• Peer-to-peer coordination. Your advocate helps schedule the physician-to-physician clinical conversation with the plan’s medical director before you file a formal appeal, and tracks the plan-specific window for requesting it.
• Deadline tracking. Your advocate tracks every deadline across every appeal level so nothing slips.
• Escalation. If Level 1 is denied, your advocate walks you through Level 2, Level 3, and beyond — or coordinates with a Medicare-experienced attorney if the case reaches that point.

Most Baba clients pay nothing out of pocket for these services when Medicare covers the work.

For the full guide to Medicare prior authorization — what it is, when it applies, the 2026 changes — see Baba’s Medicare prior authorization pillar guide.