Does Medicare Advantage Require Prior Authorization?

Yes, for some services. Medicare Advantage HMO and PPO plans are allowed to require prior authorization, which means the plan has to approve a service before it will cover it, and since January 1, 2026 the plan has 7 calendar days to decide a standard request and 72 hours to decide an urgent one (42 CFR 422.568, 422.572).

Which services need approval is set plan by plan, not by Medicare. What Medicare does set is the rulebook: what a plan may use prior authorization for, how fast it must answer, what an approval is worth once you have it, and how you appeal a no. Those rules changed meaningfully in 2024 and again in 2026, and most of what ranks for this question predates them.

What prior authorization is, and why plans use it

Prior authorization is a plan’s requirement that you, or more often your doctor’s office, get the plan’s approval before a specific item or service is provided. Without the approval, the plan may not pay.

It exists because a Medicare Advantage plan is paid a fixed amount per member to provide all of your Part A and Part B benefits, and it manages that budget by reviewing higher-cost care in advance. That is part of the same bargain that comes with an annual cap on out-of-pocket spending and, often, a lower monthly premium. It is a design feature of managed care, and it has real costs when it goes wrong: a delayed scan, a rehab admission that takes three phone calls.

Federal rules limit what the tool may be used for. A coordinated care plan may use prior authorization only for one of these purposes (42 CFR 422.138(b)):

• to confirm the presence of a diagnosis or other medical criteria that are the basis for coverage of the specific item or service;
• for basic Medicare benefits, to ensure the item or service is medically necessary under Medicare’s standards; or
• for supplemental benefits, such as dental or hearing extras, to ensure the service is clinically appropriate.

It is not supposed to be a way to apply a stricter standard than Medicare itself applies. More on that below.

Which services usually need prior authorization?

There is no single federal list. Each plan publishes its own, and it varies by carrier, by plan and by year. That is why a plan-specific claim you read online, including a statistic about “most plans,” cannot tell you what your plan requires.

The pattern, though, is consistent: plans concentrate prior authorization on care that is expensive, elective or ongoing. The Office of Inspector General at the Department of Health and Human Services, which audits these decisions, has singled out two categories where denials deserve scrutiny: advanced imaging such as MRIs, and post-acute facility stays such as inpatient rehabilitation (OIG, OEI-09-18-00260, April 2022). Its June 2026 follow-up looked specifically at skilled nursing facility admissions.

Emergencies are the hard exception. A plan is financially responsible for emergency and urgently needed services regardless of whether there is prior authorization, and it is barred from even printing an instruction to seek authorization for emergency care in the materials it gives you (42 CFR 422.113(b)(2)). If you are in a Tampa emergency room, or one in another state, nobody needs to call the plan first.

Where to find your own plan’s list:

1. The Evidence of Coverage. The medical benefits chart marks services that need approval in advance.
2. The plan’s website. Since 2026, every Medicare Advantage organization must post, by March 31 each year, a list of all items and services that require prior authorization (42 CFR 422.122(c)).
3. The Annual Notice of Change. If the plan added or dropped a requirement for next year, it is a change the notice should describe. We walked through that letter in what the Annual Notice of Change is and what to look for.

One plan type is different. A Private Fee-for-Service plan is not permitted to use prior authorization policies at all (42 CFR 422.138(a)). And referrals are a separate matter: an HMO’s requirement that your primary care doctor refer you to a specialist is not the same thing as the plan approving a service. The HMO vs PPO comparison covers referrals.

How long does a Medicare Advantage plan have to decide?

This is the part that changed in 2026. Under CMS’s Interoperability and Prior Authorization final rule, the standard deadline for a prior authorization decision on a medical item or service was cut in half (CMS-0057-F fact sheet).

Sources: 42 CFR 422.568(b), 422.572(a), and for Part D, 423.568(b) and 423.572(a).

Three details in the fine print are worth knowing.

Every deadline is a ceiling. The regulation’s actual standard is “as expeditiously as the enrollee’s health condition requires, but no later than” the number in the table.

An extension has conditions. A plan may add up to 14 calendar days only if you ask for it, or if it is in your interest because the plan needs medical evidence from an out-of-network provider that could change a denial, or because of extraordinary circumstances. It has to tell you in writing why, and tell you that you can file an expedited grievance if you disagree.

A no now comes with a reason. Beginning January 1, 2026, when a plan denies a prior authorization request for an item or service, its response to your provider must include a specific reason for the denial (42 CFR 422.122(a)). That reason is the starting point for any appeal.

The prescription side runs on its own track. If your Advantage plan includes drug coverage, a prior authorization on a pharmacy drug is a Part D coverage determination with the Part D clocks in the last row, not the 7-day rule. The 7-day rule does not apply to drugs at all.

Can a plan deny something Original Medicare would cover?

Not on a stricter standard. A Medicare Advantage plan has to cover the same Part A and Part B benefits Original Medicare covers, and since 2024 the regulations spell out how it must decide medical necessity (42 CFR 422.101):

• The plan must base the decision on Medicare’s own coverage criteria, in statute, regulation and national and local coverage determinations, along with your medical history, your physician’s recommendation and the clinical notes. It “may not deny coverage for basic benefits based on coverage criteria not specified” in those rules.
• The plan may create its own internal coverage criteria only when Medicare’s criteria are not fully established, they must be based on current evidence in widely used treatment guidelines or clinical literature, and they must be publicly accessible, with the evidence and rationale behind them.
• Every prior authorization policy has to be reviewed at least annually and approved by a utilization management committee led by the plan’s medical director, with a majority of practicing physicians, including at least one who is independent of the plan and at least one with expertise in the care of elderly or disabled people (42 CFR 422.137). No policy may be used that the committee has not approved.

Those rules were written in response to something specific. In its 2022 review of a sample of 250 prior authorization denials from 15 of the largest Medicare Advantage organizations, the Inspector General found that about 13 percent of the denied requests met Medicare coverage rules, meaning the services likely would have been approved under Original Medicare. The main causes were plans applying clinical criteria not found in Medicare’s coverage rules, and denials for insufficient documentation when the medical records already supported the service (OIG, OEI-09-18-00260).

Read that figure both ways. It means roughly seven in eight sampled denials were consistent with Medicare’s rules. It also means a meaningful share were not, which is the case for appealing a denial your doctor disagrees with.

What an approval is worth once you have it

Two protections apply after the plan says yes, and both are newer than most people’s understanding of how this works.

An approval sticks. If the plan approved a covered item or service through prior authorization, it may not later deny coverage on the basis of lack of medical necessity, and it may not reopen the decision except for good cause or reliable evidence of fraud or similar fault (42 CFR 422.138(c)).

An approval lasts through the treatment. For an active course of treatment, an approval must be valid for as long as medically necessary to avoid disruptions in care (42 CFR 422.112(b)(8)).

The same paragraph contains a rule that matters every January. If you join a Medicare Advantage plan after you have already started a course of treatment, the plan must give you a minimum 90-day transition period during which it may not disrupt that treatment or require reauthorization, even if the provider is out of network. It applies to people new to the plan and people new to Medicare.

That is directly relevant right now. Medicare Open Enrollment runs October 15 through December 7 for coverage starting January 1 (Medicare.gov). If you are mid-treatment, say partway through a series of injections or a course of physical therapy, and you are weighing a different plan for 2027, the 90-day transition is the floor under you. It is a transition and not a permanent pass: confirm before you switch whether your providers are in the new network and what the new plan will require after the 90 days.

Does Original Medicare require prior authorization?

Far less often, and that difference is one of the honest trade-offs between the two ways of getting Medicare.

In Original Medicare, prior authorization or pre-claim review currently applies to certain hospital outpatient department services, repetitive scheduled non-emergency ambulance transport, and certain durable medical equipment, prosthetics, orthotics and supplies (CMS). The provider or supplier handles it.

Two regional programs sit on top of that, and Florida’s position in them is specific:

• Florida is in the home health Review Choice Demonstration. It is one of six states, with Illinois, Ohio, Texas, North Carolina and Oklahoma, where home health agencies billing Original Medicare choose between pre-claim review and other review options. CMS extended the demonstration for an additional five years effective June 1, 2024 (CMS). The agency does the paperwork, not you.
• Florida is not in the WISeR model. The much-discussed test of prior authorization in Original Medicare runs from January 1, 2026 through December 31, 2031 in six states: New Jersey, Ohio, Oklahoma, Texas, Arizona and Washington. CMS says it “does not change Medicare coverage or payment policy” and “does not apply to people with Medicare Advantage” (CMS WISeR model). A Florida resident on Original Medicare is not affected by it, whatever the headlines suggested.

None of this makes one path right. Original Medicare with a Medicare Supplement gives you broad provider choice and little advance review, and you pay for that in monthly premium, a separate drug plan, and no built-in dental, vision or hearing extras. Medicare Advantage typically asks less in premium and caps your annual spending, and you accept networks and advance review. A $0-premium plan means no monthly plan premium; you still pay the Part B premium, $202.90 a month in 2026, and the plan’s cost-sharing when you use care. The annual Medicare cost estimator puts both paths on one page, and the parts of Medicare explained covers how they fit together.

One asymmetry belongs in the decision. Moving from Advantage back to Original Medicare is always possible during the right window, but buying a Medicare Supplement afterward may involve medical underwriting. In Florida the details matter, and we covered them in switching from Medicare Advantage to Medigap in Florida.

What to do if your prior authorization is denied

Appeal it, and do it on the clock. The process has fixed steps (Medicare.gov):

1. Read the denial notice for the reason and the date. The plan must give you written notice, and since 2026 it must give your provider a specific reason.
2. File a reconsideration with the plan within 65 days from the date on the notice. You, your representative or your doctor can file. Late filings need a reason.
3. Ask for a fast appeal if your health cannot wait. If waiting could seriously jeopardize your life, health or ability to regain maximum function, the plan must decide within 72 hours. Otherwise a standard pre-service appeal takes up to 30 days, and a Part B drug appeal up to 7.
4. Have your doctor supply the clinical case. The most common fixable problem is missing documentation. A letter that speaks to the plan’s stated reason, with the relevant notes attached, does more than a phone call.
5. If the plan upholds its denial, you do not have to do anything to reach level 2. The plan must automatically forward the case to an Independent Review Entity, an outside organization that contracts with Medicare. Further levels follow if the amount in dispute is large enough.

Does appealing work? The most recent federal evidence says it frequently does. The Inspector General’s June 2026 report examined 19 Medicare Advantage organizations, which together denied 12 percent of requests for skilled nursing facility admission in June 2024. Enrollees and providers appealed 18 percent of those denials, and when they did, the plans themselves overturned 95 percent in the enrollee’s favor (OIG, OEI-09-24-00331).

That finding covers one type of service at 19 organizations in one month, so it is not a prediction for your case. But the shape of it is hard to miss: most denials were never challenged, and almost all of the ones that were got reversed.

If you want help with an appeal from someone with nothing to sell, Florida’s State Health Insurance Assistance Program is SHINE, and CMS lists it at (800) 963-5337 (CMS SHINE contact). You can also call 1-800-MEDICARE.

How to compare plans on prior authorization during Open Enrollment

Hillsborough County alone has 133 Medicare Advantage and Part D plan options for 2026 (source: CMS CY2026 Landscape), and a shopper in St. Petersburg, Clearwater or Sarasota faces a county list of their own. Prior authorization is one of the few things about those plans you could not compare until recently. Now you can, at least in part.

Beginning in 2026, each Medicare Advantage organization must post on its website, by March 31, its prior authorization results for the previous calendar year (42 CFR 422.122(c)). The required figures include:

• the list of all items and services that require prior authorization;
• the percentage of standard requests approved, and the percentage denied;
• the percentage of standard requests approved after appeal;
• the percentage of expedited requests approved and denied; and
• the average and median time between a request and a decision, for both standard and expedited requests.

Two cautions. The figures are reported at the contract level, which can span several plans, and they exclude drugs. And a low denial rate does not by itself mean easier access; a plan that requires approval for fewer things may post a higher denial rate on the things it does review. Use the numbers as a question to ask, not a ranking.

A short checklist for anyone comparing plans for 2027:

1. List the care you already know is coming. A joint replacement, a scheduled scan, ongoing therapy, a specialty drug.
2. Look each one up in the plan’s Evidence of Coverage and note whether it needs approval in advance.
3. Ask your doctor’s office which plans they find workable. The staff who file these requests know which approvals come back in two days and which take two weeks.
4. Check the plan’s posted prior authorization figures, especially the median decision time.
5. If you are mid-treatment, plan around the 90-day transition rather than assuming it away.

Prior authorization is a reason to read a plan carefully, not a reason to rule a whole category of coverage in or out. Whether the trade is worth it depends on your doctors, your prescriptions, your health and what you would rather pay for: premium up front, or cost-sharing and review as you go.

If you would like a second set of eyes on how a plan’s rules line up with the care you expect next year, schedule a conversation with Virginia Barausky. She is based in Tampa and works with families across Florida. This article is education, not a recommendation about your situation, but sorting out what a plan will ask of you before January is a good use of half an hour.