By Core Insurance SolutionsOctober 19, 2026

Prior Authorization in Medicare: What It Is and How to Appeal

Prior authorization means your plan must approve a service, item or drug before it agrees to pay for it. Original Medicare rarely requires it. Medicare Advantage plans and Part D drug plans use it much more often. Which one you have decides how often you will hear the phrase, how long you will wait for an answer, and what you can do when the answer is no.

Core Insurance SolutionsChoose Coverage With Fewer SurprisesCore Insurance Solutions compares Medicare plans around your health needs and preferences, including prescription costs and coverage details.Explore Medicare guidance

TL;DR

Original Medicare requires prior authorization only in limited cases, such as certain durable medical equipment and repeated scheduled, non-emergency ambulance trips.
Medicare Advantage and Part D plans set their own prior authorization rules, and those rules can change every plan year.
Since January 1, 2026, Medicare Advantage plans must decide standard medical requests within 7 calendar days and expedited ones within 72 hours, and must give a specific reason for any denial.
A denial is not the final word. You have 65 days from the date of the notice to file a level 1 appeal.
Check your plan’s Evidence of Coverage and drug formulary before you need care, not after.

Original Medicare vs. Medicare Advantage vs. Part D
How long a decision should take
What the denial letter must now tell you
Why appeals are worth your time
Our perspective: look at prior authorization before you pick a plan
Before the fall enrollment deadline
Working with a local agent
FAQ
Sources

Original Medicare vs. Medicare Advantage vs. Part D

The same word means different things depending on the coverage you carry.

Coverage	How often prior authorization applies	What the request is called
Original Medicare (Parts A and B)	Limited to a short list of items and services	Prior authorization request
Medicare Advantage (Part C)	Common, set by each plan	Organization determination
Part D drug plan	Applies to drugs with coverage rules	Coverage determination

That table is the short version. The details matter, so here they are one coverage type at a time.

Original Medicare

In most cases, you don’t need approval from Original Medicare before it covers a service or item. CMS does maintain a Required Prior Authorization List for certain durable medical equipment, prosthetics and orthotics. Knee orthosis code L1832 is one item on it. If you have seen that code in a search, this is why. In practice your supplier or doctor submits the request, not you.

The other well-known exception is ambulance transport. If you get scheduled, non-emergency ambulance trips, 3 or more round trips in a 10-day period, or at least once a week for 3 weeks or more, the prior authorization program may apply to you. Emergency ambulance rides are not part of it.

Original Medicare — overview diagram

Medicare Advantage

Here prior authorization is a routine part of the plan. You may need your plan’s approval before it covers certain services or items. Each plan chooses what to include, so a service one plan covers freely may need approval in the plan next door. Common candidates are advanced imaging, surgeries, specialized treatments and expensive drugs, though your own plan’s list is the only one that counts.

The formal name for the request is an organization determination. You will see that phrase on denial letters and in plan materials. Using it when you call the plan helps the representative understand exactly what you are asking about.

Part D prescription drug plans

Part D plans list drugs on a formulary, and some carry rules such as prior authorization, step therapy or quantity limits. Step therapy means trying a lower-cost drug first. Quantity limits cap how much you can get at once. When a drug has one of these rules, your prescriber usually has to show the plan why the drug is medically necessary for you.

Three common Part D drug coverage rules

How long a decision should take

Timelines are where recent rules changed the most. As of 2026, Medicare Advantage plans must process standard prior authorization requests for medical items and services within 7 calendar days. For urgent cases, they must give an expedited decision within 72 hours. Before the change, standard timeframes were often double that.

Request	Standard	Expedited
Medicare Advantage medical item or service	7 calendar days	72 hours
Part D coverage determination	72 hours	24 hours

The plan may in some cases extend the medical timeline by up to 14 days if it needs more information, but it has to tell you in writing. If you ask yourself “how long does prior authorization take for Medicare?”, the honest answer is: up to a week for most standard Advantage requests, and about three days for a standard drug request. Faster if your doctor certifies that waiting could seriously harm your health.

If your plan misses these deadlines, write down the date of your request and who you spoke with. A missed deadline is worth raising with the plan and, if needed, with 1-800-MEDICARE.

What the denial letter must now tell you

A rule effective in 2026 requires plans to provide a specific reason for any denial. CMS says this helps patients and their doctors see which documentation or clinical criteria were missing. It is also described in CMS’s Prior Authorization API guidance, which says a payer’s response must either approve the request or deny it with the specific reason.

Read that reason carefully. In many cases “denied” means “we need more information,” such as a chart note, a lab result or proof that a cheaper drug did not work. If the reason is a missing document, the fix may be a phone call from your doctor’s office rather than a long fight.

Why appeals are worth your time

CMS has reported that when Medicare Advantage enrollees or their providers appeal a denial, plans overturn their own decision in roughly 80% of cases. Fewer than 4% of denials are ever appealed. That gap is the reason this topic matters. It does not guarantee your appeal will succeed, since every case turns on your medical records and plan terms. But it does mean that giving up after the first letter leaves a lot of covered care unclaimed.

The steps

Read the notice. Note the date, the service or drug, and the stated reason.
Call your doctor. Ask whether they can supply missing records or a statement of medical necessity. Your prescriber’s support is often the strongest part of a Part D appeal.
File within 65 days. You generally have 65 days from the date of the denial notice to file a level 1 appeal. Missing it means giving a valid reason for the delay.
Ask for a fast appeal if waiting is risky. An expedited appeal can bring a decision in 72 hours.
Keep copies of everything. Letters, call dates, names and reference numbers.

The appeals process has five levels. For Part D, level 1 appeals (called redeterminations) have a standard decision time of 7 days for benefits and 14 days for payment. For Medicare health plans, standard pre-service appeals take 30 days and payment appeals 60 days. Our own walkthrough, 5 steps to win a Medicare appeal, goes deeper on the paperwork.

If you have also been through a denial for out-of-pocket prescriptions that insurance never touched, this guide to the documents that help avoid HSA/FSA claim denials shows how much the paperwork behind a claim can decide the outcome. The principle carries over to Medicare appeals: the plan answers what the file shows.

Our perspective: look at prior authorization before you pick a plan

Most people meet prior authorization the wrong way: at the pharmacy counter or in a specialist’s office, when a plan says no. We think the better time to meet it is during plan selection.

When we work with seniors in Lakeland and the surrounding Polk County communities, we start with a health needs assessment. Which specialists do you see? Which drugs do you take, and are any of them on a formulary with extra rules? Do you expect surgery, imaging or equipment in the coming year? Those answers tell us which plan features matter. A plan with a low premium can still be a poor fit if the medicines you take need approval every time.

Three habits we encourage:

Use the Evidence of Coverage as your rulebook. Medicare guidance points to this document for what a plan covers. Because requirements can change each plan year, we suggest reviewing it annually.
Ask about the process, not just the benefit. Does the plan require approval for the services you are likely to use? Is your doctor comfortable working with it?
Do not wait for a denial to ask for help. If a request is turned down, bring us the letter. We can help you understand the stated reason and the steps for claims advocacy, and we will tell you plainly when the next move belongs to your doctor or to the plan.

Original Medicare with a Medigap plan generally avoids the plan-level approval step, though it comes with different tradeoffs, like monthly premiums and no built-in drug coverage. Medicare Advantage often has extra benefits and lower premiums but more rules. Neither is right for everyone. A fair comparison looks at your doctors, your drugs and your budget together.

— Core Insurance Solutions

Before the fall enrollment deadline

Today is October 17, 2026, so the Medicare annual enrollment period (October 15 to December 7) is open right now. This is the best window to look at how your current plan handled prior authorization this year, and whether another plan would suit you better. Questions worth asking:

Did any request I made this year get delayed or denied? Was the reason clear?
Are my regular medicines still on the formulary for next year, and do they carry new restrictions?
Are my doctors and hospital still in network? Our guide to Medicare Advantage out-of-network rules explains why this matters.
Would an HMO or PPO structure suit how I use care? See our comparison of HMO vs. PPO and prior authorization.

If you are turning 65 soon, the Medicare enrollment timeline shows when your windows open and close.

Working with a local agent

Choosing a plan is easier when someone checks the fine print with you. We are a local Lakeland brokerage that helps seniors compare Medicare Advantage, Medicare Supplement and Part D plans, review prescription costs, run annual policy audits and help with claims issues. Our services cost you nothing directly, since carriers pay us when you enroll. We do not offer every plan available in your area, so you can always call 1-800-MEDICARE or visit Medicare.gov for the full list.

See our services, browse Medicare Advantage plan options, or look at Part D plans in Lakeland if drug coverage rules are your main worry.

FAQ

Does Medicare require prior authorization?

Original Medicare generally does not, apart from a short list of items such as certain durable medical equipment and repeated scheduled, non-emergency ambulance transport. Medicare Advantage and Part D plans do use prior authorization, and each plan decides which services and drugs it applies to. Check your plan’s Evidence of Coverage or formulary for specifics.

What is another name for prior authorization?

You may see it called pre-authorization, pre-approval or precertification. In Medicare Advantage the formal term for the request is an organization determination, and in Part D it is a coverage determination. Using those terms on the phone can make your request clearer.

How do I appeal a Medicare prior authorization denial?

File a level 1 appeal within 65 days of the date on the denial notice, and ask your doctor to send supporting records. If waiting could harm your health, request a fast appeal, which can lead to a decision in 72 hours. The denial notice explains how to submit it, and our appeals guide lists the steps.

Does Medicare require prior authorization for L1832?

L1832 is a knee orthosis code that appears on CMS’s Required Prior Authorization List for Original Medicare. The supplier or provider usually handles the request. Coverage still depends on medical necessity and on the supplier being enrolled in Medicare, so confirm with your supplier before you are fitted.