One of the most frustrating aspects of Medicare Advantage for patients and their families does not show up highlighted in the marketing brochures: prior authorization. It is the requirement that your plan approve certain services in writing before you receive them, and a denial can delay or even prevent a treatment your doctor considers necessary. This guide explains how the process works, which services typically require it, and the exact steps to appeal if you are denied.
Why insurers require prior authorization
Medicare Advantage plans are run by private insurers who receive a fixed payment from Medicare per enrollee, regardless of how many services that person uses. Prior authorization is one of the main tools insurers use to control costs: they review whether a service meets their medical necessity criteria before committing to pay for it, rather than automatically paying for whatever a provider bills afterward. Medicare defends this mechanism as a way to prevent unnecessary services, but its own audits also acknowledge that many denials get overturned on appeal, which suggests the system sometimes denies too readily.
Which services typically require prior authorization
Each Medicare Advantage plan publishes its own list of services requiring prior authorization, and that list can change from year to year, so it is worth reviewing it each enrollment season. Even so, there are categories that nearly every plan requires often.
| Category | Common examples |
|---|---|
| Hospital procedures and surgeries | Elective surgeries, advanced imaging like MRIs and CT scans |
| Durable medical equipment | Wheelchairs, hospital beds, supplemental oxygen, power scooters |
| Post-acute care | Stays at rehabilitation facilities, skilled nursing care, intensive physical therapy |
| Certain Part D medications | High-cost specialty drugs, some biologics and oncology treatments |
| Out-of-network specialist referrals | Consultations with specialists outside your HMO plan's medical group |
If your plan is an HMO, review our Medicare Advantage HMO vs. PPO comparison to understand why out-of-network referrals often require an extra step that a PPO plan does not require in the same way.
Availability, cost, benefits, and eligibility vary by person, product, contract, and insurance company, as well as by your service area. Guarantees are subject to the claims-paying ability of the issuing insurance company. Karla Arámburo is not affiliated with or endorsed by Medicare or the federal government.
What happens if you are denied an authorization
When a plan denies a prior authorization request, it must send you and your doctor a written notice explaining the reason for the denial and your appeal rights. That letter matters: keep it, because it contains the exact deadlines you have to appeal and your specific plan's instructions. In the meantime, your doctor may propose an alternative covered service, or may support your appeal with additional clinical documentation.
The concrete steps to appeal a denial
The Medicare Advantage appeal process has defined levels, and understanding each one helps you know what to expect at each stage.
- Level 1 — Plan reconsideration: you ask the plan itself to review its decision. A standard appeal is resolved within up to 30 days for a service or 7 days for a drug; an expedited appeal, when waiting seriously endangers your health, is resolved within 72 hours or less.
- Level 2 — Independent Review Entity: if the plan upholds the denial, the case automatically moves to a reviewer contracted by Medicare with no relationship to your plan, who evaluates the case impartially.
- Level 3 — Administrative law judge hearing: available if the disputed amount exceeds a minimum threshold Medicare sets each year, with a formal hearing where you can present evidence.
- Levels 4 and 5 — Medicare Appeals Council and federal court: reserved for cases not resolved at earlier levels; very few appeals reach this far.
The vast majority of appeals I see with clients are resolved at Level 1 or Level 2, especially when the treating doctor submits clear clinical notes supporting the medical necessity of the service.
Practical tips for patients and families
Always request the denial in writing, even if you were told over the phone; without that document you cannot formally start the appeal. Ask your doctor to include detailed clinical notes explaining why the service is specifically necessary for your case, rather than a generic request. Mark the deadlines on a calendar as soon as you receive the notice, because missing the deadline can mean losing the right to appeal that particular service. And if your situation is urgent, explicitly request that it be processed as an expedited appeal; the plan does not always offer this automatically.
To understand the full Medicare Advantage picture before choosing a plan, review our general Medicare Advantage guide, and if comparing a plan's quality alongside its authorization rules matters to you, check our Medicare Advantage star ratings guide. If you have a chronic condition or qualify for dual eligibility, also review our D-SNP special needs plans guide, since these plans often have authorization rules tailored to specific conditions.
Choosing a plan with less prior authorization friction
I am Karla Arámburo, an independent, bilingual insurance agent licensed to serve families across Southern California, including communities like Riverside and Hemet. When I compare Medicare Advantage plans with you, I do not just look at the monthly premium: I review each plan's list of services requiring authorization and how often it applies to the treatments, equipment, or specialists you actually use, to help you choose the plan with the least friction for your specific situation.
You can call or text (619) 321-8733 or schedule a free consultation to review your specific situation. This page is general education, not individualized advice or a product recommendation.
Frequently asked questions
What exactly is prior authorization in Medicare Advantage?
It is the written approval your Medicare Advantage plan requires before you receive certain services, procedures, equipment, or medications, confirming they are medically necessary under the plan's rules. Without that advance approval, the plan can refuse to pay even if your doctor recommended it.
Does Original Medicare also require prior authorization?
Very rarely. Original Medicare (Parts A and B) requires prior authorization for only a handful of specific services. Medicare Advantage plans, by contrast, require it far more broadly, and each insurer decides on its own which services need it.
How long does an insurer have to respond to an authorization request?
For a standard request, generally up to 14 calendar days. If your doctor marks the request as urgent and waiting could seriously jeopardize your health, the plan must respond to an expedited request within 72 hours or less.
What is the difference between a standard and an expedited appeal?
A standard appeal is resolved within up to 30 days for a service, or 7 days for a Part D drug. An expedited appeal, available when waiting could seriously endanger your life or health, must be resolved within 72 hours or less.
How many levels of appeal exist if the plan keeps denying the service?
Up to five levels: reconsideration by the plan itself, review by an independent entity contracted by Medicare, a hearing before an administrative law judge, review by the Medicare Appeals Council, and finally a federal district court lawsuit, though the vast majority of cases are resolved at the first two levels.
Do I need a lawyer to appeal a prior authorization denial?
No, in most cases you do not. You can file the appeal yourself, with help from your doctor, or with the help of a licensed agent like me, who can guide you through the process and deadlines, though I cannot legally represent you before a judge.
Can I choose a Medicare Advantage plan with fewer prior authorization requirements?
Yes, to an extent. I review the list of services that require prior authorization across the plans available in your area and compare which ones require it less often for the services you use most, though no Medicare Advantage plan is entirely free of this requirement.
What happens if my appeal is decided in my favor?
The plan must authorize or pay for the service within the deadlines Medicare sets, counted from the date of the favorable decision, and must notify you in writing. If the service already happened and you paid out of pocket, the plan must reimburse you.