Medicare Advantage Prior Authorization: How It Works and What to Do If You’re Denied

What Prior Authorization Actually Is

When you have Original Medicare, you generally see a doctor, and Medicare pays its share if the service is covered and medically necessary. Medicare Advantage plans work differently. They are run by private insurers, and most of them require approval in advance for certain services. That advance approval is prior authorization, sometimes called pre-authorization or pre-certification.

It is extremely common. According to KFF, 99 percent of Medicare Advantage enrollees are in plans that require prior authorization for at least some services. The plans use it most often for expensive or high-intensity care: acute hospital stays, skilled nursing facility stays, and Part B drugs, such as infusions and injections given in a doctor’s office. It is rarely required for preventive care.

The rest of the structure is simple. Your doctor decides what you need, and the doctor’s office or the facility submits a request to your plan with supporting medical records. The plan reviews it and issues a decision, sometimes called an organization determination. If approved, the service goes ahead. If denied, you and your doctor receive a written notice explaining why.

Prior authorization is different from a referral. A referral is your primary care doctor’s permission to see a specialist, which some HMOs require. Prior authorization is the plan’s own approval. A service might need one, the other, or both, which is why you should ask.

The Rules the Plan Has to Follow

Plans do not get to set prior authorization however they like. Federal rules, which CMS tightened in changes that took effect in 2024 and again in 2026, set limits. Here is what they say, in plain terms.

• Prior authorization is meant to confirm a diagnosis or decide whether a service is medically necessary. It is not meant to be a general-purpose barrier.
• Plans generally must follow Original Medicare’s coverage rules, including national and local coverage determinations. They cannot use stricter internal criteria to deny care that Original Medicare would cover. This is one of the most important points for patients to know.
• An approval has to last long enough to avoid disrupting care. For ongoing treatment, the approval should be valid for as long as is medically necessary, based on your treating provider’s recommendation.
• If you are new to a plan and in the middle of a course of treatment, plans generally must allow a transition period, 90 days under the rule, without requiring a new prior authorization for that treatment.
• Once a plan approves a service, it generally cannot turn around and deny payment because it later decides the service was not medically necessary, except for good cause such as fraud.

The decision timeframes also changed. According to KFF and CMS, starting in 2026, plans must decide standard prior authorization requests for medical services within seven calendar days, down from the previous 14. Expedited requests must be decided within 72 hours. In limited situations, such as when you ask for more time or the plan is waiting on additional medical evidence, a plan may extend a standard decision by up to 14 days and must tell you why in writing. Plans must also give a specific reason when they deny a request and must report certain prior authorization data publicly, such as which services require approval, how often requests are approved and denied, and how long decisions take. Rules for Part B drugs and Part D prescription drugs have their own timeframes (CMS’s 2026 prior authorization timeframes do not cover drugs), so ask your plan if your request involves a drug.

These rules set a floor. They do not eliminate delays or disagreements, but they are useful to know when you are talking with a plan.

How Often Are Requests Denied, and Does Appealing Work?

KFF analyzed the prior authorization figures that the largest insurers were required to post publicly for calendar year 2025 and found that, on average, Medicare Advantage insurers denied about 12 percent of standard prior authorization requests. The figures cover medical services, not prescription drugs, and other analyses using different data have found lower denial rates, so treat any single number as a rough guide.

The more striking finding is what happened on appeal. KFF reported that denials are rarely appealed, but when they are, a large share are overturned: on average, 67 percent of appealed standard prior authorization denials in Medicare Advantage were overturned. KFF notes that a high overturn rate could mean the first decision should have been different or that the original request was missing documentation, and that the reported data has gaps. The share overturned also varied widely from one insurer to another.

Be careful with that figure. It does not predict the outcome of your own appeal, and it does not mean every denial is wrong. What it does show is that a denial is not the final word, and that most people never test it.

When You Get a Denial: Your First Three Moves

Denial notices can feel final, and they are written in dense language. Take a breath and do these things in order.

First, read the notice for the reason. The plan must tell you why. Common reasons include the plan decided the service was not medically necessary, the request was missing information, the provider was out of network, or the service is not a covered benefit. The reason determines your strategy.

Second, call your doctor’s office. Ask whether they have already seen the denial, what the clinical reason for the request was, and whether they can request a peer-to-peer conversation. In a peer-to-peer, your doctor speaks directly to a physician reviewer at the plan. Many denials that reflect missing information or a misunderstanding are resolved this way, before a formal appeal.

Third, note the deadline. You or your doctor generally have 65 days from the date on the denial notice to file an appeal. Medicare.gov says that if you miss the deadline, you can still file but you must give a reason for the delay. Put the date on your calendar the day you receive the notice.

The Appeal Process, Step by Step

Step	Who reviews	Timing
Level 1: plan reconsideration	The plan	30 days (care), 60 days (payment), 7 days (Part B drug)
Fast appeal	The plan	72 hours
Level 2	Independent Review Entity, automatic	Same timeframes as Level 1
Levels 3 to 5	Hearing office, Appeals Council, federal court	60 days to request each

Medicare Advantage appeals have five levels. Most issues are resolved in the first one or two.

Level 1 is a plan reconsideration. You, your representative, or your doctor files the request with the plan, following the instructions on the denial notice. Medicare.gov lists the standard decision timeframes as 30 days for a request about care you have not yet received, 60 days for a payment request, and seven days for a Part B drug.

If your doctor says that waiting for a standard decision could seriously jeopardize your life, health, or ability to regain maximum function, you can ask for a fast appeal, also called an expedited reconsideration. The plan has 72 hours to decide. If your doctor supports the request, the plan generally must expedite it.

Level 2 is an independent review. If the plan upholds its denial, the case goes automatically to an Independent Review Entity, a reviewer that is not part of the plan. You do not have to start a second appeal yourself.

Levels 3 through 5 are available if you disagree with the independent review: a hearing before an administrative law judge at the Office of Medicare Hearings and Appeals, then the Medicare Appeals Council, then federal district court. Each has a 60-day filing window, and the higher levels have minimum dollar thresholds that change each year. Few cases get that far.

For the appeal itself, include your name, your Medicare number, a description of the service and the dates, why you disagree, and supporting documents. A letter from your doctor explaining why the service is medically necessary, with test results and clinical notes, is the single most useful attachment.

What Makes an Appeal Stronger

You can improve your odds by making the reviewer’s job easy. Ask your doctor to address the denial reason directly. If the plan said the service was not medically necessary, the letter should explain why, citing your diagnosis, symptoms, prior treatments you have tried, and relevant clinical guidelines. If the denial said information was missing, send the missing information.

Keep copies of everything and note the date and time of every call. Ask for the name of the person you spoke with and a reference number. If a deadline is close and your health is at stake, request the fast timeline in writing and ask your doctor to state in the letter that waiting is risky.

You can also ask for help. The state Health Insurance Assistance Programs, which in Ohio is OSHIIP, offer free counseling and can sometimes help with appeals. The Medicare Rights Center also runs a national helpline for appeal questions. An attorney who handles Medicare cases can advise on complicated disputes, and we are not able to offer legal advice.

Step by Step: The Life of a Request

Knowing the sequence helps you see where a delay or a problem is likely to occur, and what you can do at each point.

• Your doctor recommends a service, such as an MRI, a surgery, a course of treatment, or an infused drug.
• The doctor’s office checks whether your plan requires prior authorization for it. Ask the office to do this before scheduling anything expensive.
• If it does, the office submits a request with your records. Incomplete records are a common reason for delay or denial.
• The plan reviews the request against Medicare’s coverage rules and decides within its timeframe: seven calendar days for a standard request, 72 hours for an expedited one.
• You and your doctor receive the decision. An approval should state what is approved and for how long. A denial must state the reason.
• If it is approved, schedule the service within the approval period and use a provider who is in network, since the approval does not change network rules.
• If it is denied, you move into the options described below, starting with a call to the doctor’s office.

Keep a simple log as you go: the date the request was submitted, who submitted it, any reference number, and each date you called. That record is the most useful tool you can have if you need to appeal.

How It Differs for Original Medicare, Advantage, Medigap, and Part D

People often ask about prior authorization as if it worked the same way everywhere. It does not, and knowing the difference helps you choose coverage and handle a denial.

Coverage	Prior authorization	If a service is denied
Original Medicare	Far fewer services (plus a pilot in Ohio); ask your provider	Appeal through the process on your Medicare Summary Notice
Medicare Advantage	Common; most plans use it for some services	Plan reconsideration, then independent review
Medigap	The policy does not approve services; it follows what Medicare approves	Appeal the Medicare decision; Medigap pays its share after
Part D drug plan	Some drugs need approval or an exception	Coverage determination or exception request, then appeal

With Original Medicare, you generally see a doctor who accepts Medicare and the program pays its share if the service is covered and medically necessary. Advance approval is the exception rather than the rule, though some items and services do have requirements, so it is worth asking the provider. If a claim is denied after the fact, your Medicare Summary Notice explains how to appeal.

With a Medigap policy, the insurer is not deciding whether you get care. It pays its share of services that Original Medicare approves. If Medicare denies a service, the Medigap policy generally has nothing to pay, so the appeal goes through Medicare. That is one of the reasons some people value the predictability of Original Medicare plus Medigap, and it is fair to weigh that against the other things Medicare Advantage offers, such as a yearly out-of-pocket limit and extra benefits.

With a Medicare Advantage plan, the plan makes the advance decision, and the appeal process in this post applies.

With Part D, drug approvals work differently. The plan makes a coverage determination, and if a drug is not covered or has a restriction, you can ask for an exception with a statement from your prescriber. Once the plan has your prescriber’s supporting statement, it generally must answer within 72 hours for a standard exception request and 24 hours for an expedited one. Our overview of Medicare Part D explains the benefit.

Reducing the Chance of a Surprise

Prior authorization problems are easier to prevent than to fix. Before a planned procedure, imaging, or hospital stay, ask the doctor’s office two questions: does the plan require prior authorization for this, and has it been approved? Do not assume. Ask for the approval confirmation, and for a procedure that is expensive or ongoing, ask how long the approval lasts.

Before you choose a plan in the first place, look at the rules. Our guide to the different types of Medicare Advantage plans explains how HMOs and PPOs handle referrals and approvals, and our plan comparison checklist includes a step for reading those rules before you enroll. The Annual Notice of Change will also tell you if a plan is adding prior authorization requirements for services you use. If you are weighing Medicare Advantage against Original Medicare with a supplement, it is fair to consider this in the comparison. Original Medicare generally requires prior authorization for far fewer services, although a federal pilot that began in January 2026 in Ohio and five other states adds prior authorization for a short list of select services, such as certain skin substitutes and nerve stimulator implants. CMS publishes the list, and it can change, so ask your provider. Medicare Advantage plans offer features such as an out-of-pocket limit and extra benefits. Each trade-off is real, and which matters more depends on your health and preferences. Our overview of Medicare Supplement plans covers the other side.

Costly Mistakes to Avoid

• Assuming the doctor’s office handled it. Staff are busy, and approvals can fall through. Ask for confirmation that the approval exists, along with the date range and the service it covers.
• Having the service before the approval arrives. A plan may refuse to pay for care it did not approve first, and you could be billed. If a service is urgent, ask about an expedited request rather than going ahead without approval. Emergency care is different, and plans must cover emergencies without advance approval.
• Missing the 65-day appeal deadline. The clock runs from the date on the denial notice, not from when you finished talking to your doctor. Put the date on your calendar the day the notice arrives.
• Treating a conversation as an appeal. A peer-to-peer call between your doctor and the plan’s reviewer can resolve a denial, but ask the plan whether it counts as a formal appeal and whether your deadline is still running.
• Accepting a verbal denial. Ask for the decision and the reason in writing. Your appeal rights depend on the written notice.

Three Pictures of How This Can Play Out

These are hypothetical scenarios to show the reasoning, not real cases.

Picture a retiree whose surgeon recommends a knee procedure. The surgeon’s office submits a request and the plan denies it as not medically necessary. The retiree calls the office, which says the notes did not include the physical therapy she had already tried. The surgeon requests a peer-to-peer call and sends the additional records. The plan reverses its decision. The fix was missing documentation, and it was settled without a formal appeal.

Picture a woman who receives a payment denial for a service she already had. The same 65-day appeal clock applies. She calls the billing office, which finds that the plan had approved the service but the claim was coded incorrectly. A corrected claim is submitted. She never needed to appeal, and she did not pay the bill while it was sorted out.

What to Gather and What to Ask

When you are dealing with a denial, gather these:

• The denial notice, with its date and reason.
• Your plan’s name, member ID, and the reference number for the request.
• Your doctor’s notes, test results, and a list of treatments you have already tried.
• Your log of calls and dates.

Questions to ask the plan:

• What is the specific reason for the denial, and what criteria were used?
• What information would change the decision?
• What is my deadline to appeal, and how do I file?
• Can this be expedited, and what does my doctor need to say to request that?
• Is there a peer-to-peer option, and does it affect my deadline?

Also ask your doctor’s office whether they sent all your records, whether they will write a supporting letter, and whether a covered alternative makes sense while you wait.

If the Appeal Does Not Go Your Way

An appeal that fails at the plan level goes automatically to an independent reviewer. If that reviewer also upholds the denial, you still have further levels, and a Medicare Rights Center counselor or a state counselor can help you decide whether to continue.

You also have other tools. A complaint, which Medicare calls a grievance, is the right route for problems with how a plan treated you, such as long hold times or poor communication, as opposed to a coverage decision. You can file one with the plan, and you can call 1-800-MEDICARE if you need help.

If a plan’s rules are a recurring problem, you can use the next enrollment window to change plans. The Annual Enrollment Period, described in our guide to the Annual Enrollment Period, runs October 15 through December 7, and people in Medicare Advantage can make one change from January 1 through March 31. If you are thinking of returning to Original Medicare with a Medigap policy, find out first whether you could qualify, because in most states the insurer may ask health questions. The Ohio page on Medigap rules is a good starting point for Ohio residents.

If care cannot wait, say so clearly to your doctor and the plan. Ask your doctor about an alternative that does not need approval while the decision is pending, and use the fast appeal when your doctor supports it. That is a medical decision for you and your doctor. We cannot give medical or legal advice.

Frequently Asked Questions

Does Medicare Advantage require prior authorization?

Most plans do, for at least some services. KFF reports that 99 percent of Medicare Advantage enrollees are in plans with prior authorization requirements, most often for hospital stays, skilled nursing care, and Part B drugs.

How long does a plan have to decide a prior authorization request?

Under the federal rule that took effect in 2026, plans generally must decide standard requests for medical services within seven calendar days, with limited extensions, and expedited requests within 72 hours. Drug requests follow different timeframes.

How long do I have to appeal a Medicare Advantage denial?

Generally 65 days from the date on the denial notice. If you miss it, you can still file but need to explain the reason for the delay.

Can I get a fast appeal?

Yes, if your doctor says that waiting for a standard decision could seriously jeopardize your life, health, or ability to regain maximum function. The plan then has 72 hours to decide.

What happens if the plan upholds its denial on appeal?

The case goes automatically to an independent reviewer outside the plan. If you still disagree, further levels of appeal are available.