Prior Authorization

Medicare Denied Prior Authorization Request

Name: Medicare Denied Prior Authorization Request
Creator: Barley Billing Team
Published: 2026-03-26

Written by Barley Billing Team, Medicare Billing Experts | Fact-checked against primary CMS sources | Last reviewed October 2, 2026

Does this sound like what happened?

"My Medicare plan denied my prior authorization request"

"I was told the requested service has not been approved"

"My plan refused to authorize a service my doctor recommended"

"The prior authorization request was denied before I had the procedure"

Let's identify whether this is a Medicare Advantage denial or an Original Medicare non-affirmation, then check the appropriate review process.

What This Means

If you have Medicare Advantage, your plan reviewed a request for advance approval and denied it. You can ask the plan to reconsider before receiving the service. If you have Original Medicare, the contractor or review program may instead have issued a prior-authorization non-affirmation. That is a preliminary review decision, not a denied claim with the same appeal route.

For Original Medicare, ask your provider to review and resubmit the request. For example, CMS’s current WISeR operational guide permits resubmissions and a peer-to-peer review process. A non-affirmation itself is not appealable. If a claim is later submitted and denied, that claim decision can be appealed; the Original Medicare redetermination deadline is 120 days after receipt of the MSN, presumed five days after its date unless shown otherwise. The Medicare Advantage appeal instructions below apply to plan denials.

Why This Happens

The plan didn’t find the service medically necessary. Based on the information submitted, the plan determined the service doesn’t meet their criteria for medical necessity for your condition.
The documentation was incomplete. Your provider may not have included enough clinical information to support the request. This is one of the most common and fixable causes.
The plan requires a different treatment first. Some plans use “step therapy,” which means they require you to try a less expensive treatment before approving the requested one.
The service isn’t covered under your plan. The service may be excluded from your specific plan’s benefits, separate from the prior authorization question.
Coding or administrative errors. The wrong diagnosis code, procedure code, or other administrative details on the request can trigger a denial.

Should You Appeal?

Appeal outlook: Mixed

Medicare Advantage prior authorization denials can be appealed before care. A 2022 OIG investigation found that 13% of Medicare Advantage prior authorization denials would have been approved under Original Medicare’s standard coverage rules. That means some services are being denied by MA plans even though Medicare would normally cover them.

When people do appeal, the results are encouraging. KFF found that 80.7% of appealed prior authorization denials in Medicare Advantage were fully or partially overturned in 2024 — yet only about 11.5% of denied requests were appealed in the first place.

Your appeal is strongest when your doctor provides detailed clinical documentation explaining why this specific service is needed for your condition.

What To Do Next

Identify your coverage and ask your doctor to review the decision. For a Medicare Advantage denial, gather the missing records or clinical explanation for the plan appeal. For an Original Medicare non-affirmation, ask the provider which correction, resubmission or program review process applies.
Ask about a peer-to-peer review. Your provider can often request to speak directly with a medical director at your plan to discuss the case. This is an informal but sometimes effective step before or during the formal appeal.
For Medicare Advantage, file an appeal promptly. Follow the denial notice; the usual filing window is 65 days from its date. Standard pre-service appeals generally have a 30-day decision deadline, or 72 hours for an expedited appeal when the health criteria are met. For Original Medicare, use the resubmission route above; appeal a subsequent claim denial using the MSN instructions if one occurs.
Ask about alternative treatments. If the plan denied the specific service, ask your doctor whether there’s an alternative that the plan would cover. You can pursue the alternative while also appealing for the original service.
Request the plan’s clinical criteria. You have the right to ask your plan for the specific guidelines they used to make their decision. This helps you understand exactly what documentation is needed for a successful appeal.
Get help if you need it. Your State Health Insurance Assistance Program (SHIP) offers free counseling and can help you with the appeal process. Call 1-800-MEDICARE (1-800-633-4227) to find your local SHIP.

Sources

OIG: Some Medicare Advantage Organization Denials of Prior Authorization Requests Raise Concerns About Beneficiary Access to Medically Necessary Care (2022)
KFF: Medicare Advantage Insurers Made Nearly 53 Million Prior Authorization Determinations in 2024
Medicare.gov: Filing an Appeal
CMS: Reconsideration by the Medicare Advantage (Part C) Health Plan — the Level 1 appeal process for MA prior authorization denials, including the 30-day standard and 72-hour expedited decision deadlines
CMS: WISeR Provider and Supplier Operational Guide, sections 4.4 and 10 — resubmission/peer-to-peer review and the distinction between non-affirmation and an appealable denied claim.
CMS: Original Medicare redetermination — claim appeal filing and receipt rules.

Not sure if your denial is worth appealing? Check your notice against Medicare's rules →

Appeal Deadlines — Check Your Notice for Exact Dates

Original Medicare

No claim appeal for a prior-authorization non-affirmation. A later claim denial has a separate 120-day appeal deadline from MSN receipt (presumed 5 days after its date).

Medicare Advantage

65 days from the date on your denial notice

Not sure which you have? Check the top of your denial notice. If it names a private insurance company (like Humana, UnitedHealthcare, or Aetna), you have Medicare Advantage. If it says "Centers for Medicare & Medicaid Services," you have Original Medicare.

Frequently Asked Questions

What's the difference between a prior auth denial and a claim denial?

A Medicare Advantage prior-authorization denial concerns approval before care, and you can request a plan appeal before receiving the service. An Original Medicare prior-authorization non-affirmation generally is not an appealable claim decision; the provider can correct and resubmit the request. A later denied claim has separate appeal rights.

Can my doctor still provide the service if the prior auth was denied?

Before proceeding, ask the provider and insurer for a written explanation of coverage and what you might owe. For Medicare Advantage, you can appeal the prior-authorization denial before care. For Original Medicare, ask about correcting or resubmitting the non-affirmed request. Do not assume that receiving the service guarantees Medicare payment.

How quickly will my appeal be decided?

For Medicare Advantage plans, standard prior authorization appeals must be decided within 30 calendar days. If your health could be seriously harmed by waiting, you or your provider can request an expedited appeal, which must be decided within 72 hours.

What if my doctor says I need this service urgently?

For Medicare Advantage, ask your doctor to request an expedited appeal if waiting could seriously jeopardize your life, health or ability to regain maximum function. The usual decision deadline is 72 hours. For an Original Medicare non-affirmation, ask the provider about the applicable program's expedited resubmission or peer-to-peer review process; it is not a Medicare Advantage appeal.

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This information is for educational purposes only and is not legal or medical advice. Always verify with your doctor's office and insurance company.