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Medicare Prior Authorization: What It Is and How to Get It

Patient asks clinician about prior authorization

Prior authorization means approval has to be given before Medicare or your plan will pay for a service, item or drug. Original Medicare rarely requires it. Medicare Advantage and Part D plans use it often. Most of the time your doctor’s office handles the request, and your job is to know when it applies, what the deadlines are, and what to do if the answer is no.

This guide covers each part of Medicare, the new 2026 test in Original Medicare, the timelines plans must follow, and the steps for a denial. We are a Colorado brokerage that helps people choose plans, so we also explain how your plan choice changes how often you run into this.

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TL;DR

Original Medicare generally does not require approval for most services. Medicare Advantage plans may require it before certain services or supplies are covered.
A federal test called WISeR began January 1, 2026, and applies prior authorization to selected services in Original Medicare, but only in six states. It is not a nationwide rule for every service.
For Medicare Advantage, standard requests are generally decided within seven calendar days and expedited requests within 72 hours.
If you are denied, the notice tells you how to appeal. You generally have 65 days from the notice date to ask for reconsideration.
Prior authorization rules differ plan by plan, so check them before you enroll, not after you need a procedure.

What prior authorization means in Medicare
Original Medicare: mostly no, with exceptions
WISeR: the 2026 change in Original Medicare
Medicare Advantage: where you will meet it most
Part D: prescription drugs
Dental and other add-on coverage
How to get prior authorization
If a request is denied or delayed
How to choose a plan with prior authorization in mind
Our perspective
Get help comparing plans in Colorado
FAQ
Sources

What prior authorization means in Medicare

Prior authorization is a cost-control process. The American Medical Association describes it as a requirement that providers get approval before a service is performed or a prescription is filled. The AMA also notes it generally does not apply in Traditional Medicare except for specific programs.

Three things are easy to mix up:

Prior authorization: approval before the service is given.
Pre-claim review: CMS distinguishes this from prior authorization. It happens before the claim is submitted, even though the provider may deliver the service first.
Coverage determination: the term Part D uses when you or your prescriber ask the plan to decide on a drug.

KFF, a health policy research group, explains that insurers use prior authorization to cut unnecessary or inappropriate care. It can also cause delays, denials and extra paperwork. Both sides of that tradeoff are real, which is why the details of your plan matter.

Original Medicare: mostly no, with exceptions

Original Medicare: mostly no, with exceptions — overview diagram

If you have Part A and Part B without a Medicare Advantage plan, you can usually see any doctor who accepts Medicare and get covered care without asking permission first. That is one of the main differences from Medicare Advantage. Our Medicare Advantage vs. Medigap page walks through that tradeoff in full.

The exceptions are specific programs run by CMS:

Required Prior Authorization List for equipment. Certain durable medical equipment, prosthetics, orthotics and supplies (DMEPOS) need approval first. A January 13, 2026 Federal Register notice added seven codes (five orthoses and two pneumatic compression-device codes) effective April 13, 2026. The 67 codes already on the list stayed on it.
Hospital outpatient department services. CMS runs a prior authorization process for certain services, and it is a condition of payment for those services.
Other initiatives. Kiplinger lists examples such as non-emergency ambulance transport among services that typically need approval.

In each case the provider or supplier, not you, submits the request and the supporting medical documentation to the Medicare Administrative Contractor (MAC). The MAC sends back an affirmed or non-affirmed decision.

WISeR: the 2026 change in Original Medicare

The question we hear most this year is whether Medicare now requires prior authorization for everyone. It does not.

CMS says the WISeR model launched January 1, 2026, and runs through December 31, 2031. It operates in six states and does not cover all items and services. Participating contractors began accepting requests January 5, 2026, for services furnished on or after January 15, 2026. The Congressional Research Service describes it as a six-state test, not a universal new requirement.

What this means for you:

If you live in a WISeR state and have Original Medicare, some selected services may need approval. Check the CMS WISeR page for the current state and service lists.
If you live elsewhere, including Colorado, you will not see WISeR requests, though the equipment and hospital outpatient programs above still apply nationwide.
If you have Medicare Advantage, WISeR is not what governs you. Your plan’s own rules do.

KFF cautions that expanding prior authorization can improve oversight while raising the risk of delayed or denied care. Policy here may keep changing, so confirm current details with CMS before relying on any summary, including ours.

Medicare Advantage: where you will meet it most

Medicare Advantage plans are run by private insurers, and prior authorization is common among them. KFF says it was historically rare in Traditional Medicare but common in Medicare Advantage. Reviewing plan rules is a large part of what we do in a Medicare Advantage consultation.

What plans may use it for

According to a CMS memo on coverage criteria and utilization management, coordinated-care plans may use prior authorization only to:

confirm a diagnosis or other medical criteria,
make sure a service is medically necessary, or
decide whether a supplemental benefit is clinically appropriate.

The same guidance says it should not delay or discourage care. It generally is not permitted for emergency, urgently needed or stabilization services, and MA PPO plans may not apply it to covered out-of-network services.

In practice, plans commonly ask for approval on things like inpatient stays, advanced imaging, certain surgeries, specialty drugs and some home health or equipment. The exact list is in your plan’s Evidence of Coverage. It changes by plan and by year, so we do not give a universal list here.

Utilization management is more than prior authorization

“Utilization management” is the umbrella term for the tools plans use to control spending. Prior authorization is one. Others include referrals, step therapy and quantity limits. The Medicare Advantage rules above govern how a plan applies these to medical services.

Part D: prescription drugs

Part D plans apply the idea to medications. Medicare.gov explains that plans may have rules such as prior authorization, step therapy and quantity limits. Prior authorization means you or your prescriber must get approval before the plan covers certain drugs. Your prescriber may need to show the drug is medically necessary.

Plans may also use it when they cover a drug for some conditions but not others.

A frequent question is which three drugs need prior authorization. There is no fixed national list, and we will not give you three names that may not apply to your plan. Each plan publishes its own formulary, which marks drugs that need approval, and it changes each year. The drugs that most often carry restrictions tend to be expensive or specialty medications, but only your formulary settles it.

Two protections are worth knowing:

When your coverage begins, you may get a one-time 30-day transition fill of a drug you already take that the plan requires approval for.
You or your prescriber can ask the plan for an exception to a rule.

Before you enroll in or switch a drug plan, we check your medications against the formulary. Our Part D plan page explains how.

Dental and other add-on coverage

Dental, vision and hearing benefits inside a Medicare Advantage plan, or in a stand-alone policy, run on their own rules. Dentists often ask insurers for approval before costly work, and it helps to see how dental preauthorization works before you schedule a major procedure. Ask your dentist’s office to confirm approval in writing before treatment.

How to get prior authorization

The process depends on your coverage, but the pattern is the same.

Four steps for getting prior authorization

Step 1: Ask your doctor’s office to check

Prior authorization typically happens between your doctor and Medicare or your plan. Before a procedure, scan, equipment order or new drug, ask the office: “Does my plan need prior authorization for this, and have you submitted it?”

Step 2: The provider submits the request

For Original Medicare, providers can submit requests by fax, mail, electronic submission of medical documentation or MAC electronic portals, according to Healthline. For DMEPOS items on the required list, the request must go in before the item is furnished and the claim is submitted. It includes the written order or prescription, relevant medical-record information and supplier documentation, per the Federal Register.

For Medicare Advantage and Part D, the request goes to your plan. Your prescriber or the provider submits it, and you can often follow up with the plan’s member services line.

Step 3: Know the timeline

Under the CMS-0057-F rule, Medicare Advantage organizations must decide medical-service requests as quickly as your condition requires. The general limits are:

Request type Decision deadline Standard 7 calendar days Expedited (your health could be seriously harmed by waiting) 72 hours

CMS says these deadlines are in calendar time, apply however the request arrives (portal, fax, phone or API), and may be extended by up to 14 calendar days under applicable conditions.

Step 4: Check the status

If you have Original Medicare, you can call 1-800-MEDICARE (1-800-633-4227, TTY 1-877-486-2048) to check the status of a request. If you have Medicare Advantage or Part D, call the member services number on your plan card.

If a request is denied or delayed

A denial is not the end. Many are overturned when the right documentation reaches the plan.

Medicare Advantage denial. Follow the instructions in the denial notice to request reconsideration. You, your representative or your provider must file within 65 days of the notice date. A late appeal needs a reason, per Medicare.gov. Because these plans are private, your plan materials hold the specific appeal details, as the Medicare Appeals booklet notes.

Part D denial. You, your representative or your prescriber can request a coverage determination, orally or in writing, from the plan (same booklet).

Practical tips:

Ask your doctor for a letter explaining why the service or drug is medically necessary, and why alternatives did not work or are unsuitable.
Keep copies of every notice, with dates.
If waiting would risk your health, ask for an expedited review.
Do not skip a medically urgent service because approval is pending. Ask your doctor about options, and remember that emergency care generally is not subject to prior authorization in Medicare Advantage.

Free help. If a concern stays unresolved, 1-800-MEDICARE can pass your inquiry to the Medicare Beneficiary Ombudsman. State Health Insurance Assistance Programs (SHIPs) offer free, local counseling on rights and billing problems. In Colorado, the Division of Insurance runs SHIP for Medicare enrollees.

If you would like someone to help you prepare an appeal, our appeals and grievance assistance is for exactly that.

How to choose a plan with prior authorization in mind

Since approval rules mostly come from your plan, compare them when you shop. A few questions:

Which of my regular services and drugs need approval? Check the Evidence of Coverage and formulary, not the brochure.
Are my doctors and hospitals in the network? Out-of-network care under an HMO can be a bigger problem than approval.
How do I weigh predictability against premium? Original Medicare with a Medigap plan has fewer approval steps in general. Medicare Advantage often has lower premiums and extra benefits but more rules. We explain the tradeoffs in Medigap plans and Medicare Advantage plans.
When can I switch? The enrollment periods limit when you can change, so it is better to learn about a plan’s rules before you enroll. Switching can also leave gaps, which we cover in changing Medicare Advantage plans in Colorado.

Our perspective

Most of the prior authorization trouble we see does not come from the rule itself. It comes from people learning about it at the worst moment: a scan has been scheduled, a drug is at the pharmacy counter, and the plan says no.

We think the fix is simple, and it happens before enrollment. As independent, licensed brokers working across multiple carriers, we can look at your actual doctors, prescriptions and budget and show you how different plans would treat them. Because we are paid by carriers when you enroll, at no direct cost to you, we say this plainly: a plan with fewer approval steps is not automatically better for you, and one with more steps is not automatically worse. The right answer depends on your health, your providers and what you want to spend.

We also stay with clients after they enroll. When a denial arrives, or at the annual review each fall, we help you read the notice, collect what your doctor needs to send and decide whether to appeal or change plans.

— Zach

Get help comparing plans in Colorado

If you are turning 65, or you want to see how your current plan handles approvals, we can compare options with you. Our services page lists everything we offer, including Medicare Advantage consultations, Plan G and Plan N quotes, annual enrollment help and appeals support. You can also start from our Medicare planning page.

FAQ

Does Medicare require prior authorization?

Original Medicare generally does not, except for specific programs such as certain equipment items and hospital outpatient services, plus the WISeR test in six states. Medicare Advantage and Part D plans use it more often. Your plan documents show exactly what applies to you.

Is Medicare going to require prior authorization in 2026?

Only in a limited way. WISeR started January 1, 2026, covers selected services in six states, and runs through 2031. It does not apply to every Original Medicare service, and CMS announces changes on its WISeR page.

How do I contact Medicare about prior authorization?

With Original Medicare, call 1-800-MEDICARE (1-800-633-4227; TTY 1-877-486-2048) to check the status of a request. With Medicare Advantage or Part D, call the member services number on your plan card, because the private plan makes the decision.

How long does a Medicare Advantage prior authorization take?

Plans must generally decide standard requests within seven calendar days and expedited requests within 72 hours. Under certain conditions the deadline can be extended by up to 14 calendar days.

What can I do if my request is denied?

Read the denial notice, which explains how to request reconsideration. For a Medicare Advantage plan, file within 65 days of the notice date. Ask your doctor for a letter supporting medical necessity, and call your state SHIP for free counseling.