Medicare Prior Authorization
May 20, 2026
Medicare prior authorization is your plan's requirement that you or your doctor get approval before you receive certain services, drugs, or equipment, so the plan can confirm the care is medically necessary before it agrees to pay. It shows up far more often in Medicare Advantage than in Original Medicare, and if a request is denied, you have a defined path to appeal it.
Starting in 2026, a federal rule tightens how quickly plans must respond to these requests, which matters because slow decisions have been one of the most common complaints from Medicare Advantage members. This guide covers where prior authorization applies, how to submit a request that doesn't stall, and what to do if your plan says no.
Quick Answer
Medicare prior authorization means your plan must approve certain services, drugs, or durable medical equipment before you receive them, or before the plan will pay the claim. It is common in Medicare Advantage plans, rare in Original Medicare, and Medigap plans simply follow whatever Original Medicare has already approved. Under a CMS rule taking effect in 2026, Medicare Advantage plans must decide expedited requests within 72 hours and standard requests within 7 calendar days. If a request is denied, you can appeal, usually starting with a reconsideration by the plan.
Prior authorization requirements vary by coverage type.
Medicare Advantage plans use prior authorization heavily, especially for specialty drugs, imaging such as MRIs and CT scans, durable medical equipment, and inpatient hospital admissions. Medicare Advantage is the private-plan alternative to Original Medicare, regulated by the Centers for Medicare & Medicaid Services (CMS), and insurers rely on prior authorization as one of their main tools for managing utilization and cost. See our comparison of Medicare Advantage HMO vs. PPO plans for how authorization rules can differ by plan type.
Original Medicare, the federal fee-for-service program covering Part A hospital care and Part B outpatient care, requires prior authorization for a short, specific list of items. That list includes certain durable medical equipment and a handful of outpatient department procedures, such as some cosmetic-adjacent surgeries, that CMS added to reduce unnecessary billing.
Medigap plans, also called Medicare Supplement plans, do not run a separate prior authorization process. They pay secondary to Original Medicare, so once Medicare approves and pays a claim, a Medigap plan such as Plan G picks up its share automatically.
If you are weighing Medicare Advantage against Original Medicare plus a Medigap plan, how often prior authorization applies is one of the real trade-offs to factor in. Our Medicare Advantage vs. Supplement comparison walks through the others, including premiums and provider networks.
New 2026 CMS Prior Authorization Timelines
Under CMS's Interoperability and Prior Authorization Final Rule, Medicare Advantage plans and other affected payers must send prior authorization decisions within 72 hours for expedited requests and 7 calendar days for standard requests, starting in 2026. According to CMS, the rule also requires plans to give a specific reason for any denial and to build electronic systems designed to speed up the review process. Ask your plan whether your request is being treated as expedited or standard, since that determines which clock applies. Read the CMS fact sheet on the final rule for the full timeline.
How to Navigate a Prior Authorization Request
- Ask your doctor's office to submit the prior authorization request; they have the clinical documentation and forms the plan requires.
- Get the approval in writing before you receive the service, drug, or equipment.
- Build in extra time. Standard decisions can take up to 7 calendar days, and some non-Advantage payers still take longer.
- Keep a written log of who you spoke with at the plan, what they said, and the date of each call.
- Confirm the procedure or billing code on the authorization matches exactly what your doctor's office plans to bill.
Plans must explain a denial in writing and tell you how to appeal, and most appeals have a short filing window, often around 60 days from the date of the denial notice. The Medicare appeals process for a prior authorization denial generally follows five levels:
- Reconsideration by the plan
- Independent Review Entity (IRE) review
- Administrative Law Judge (ALJ) hearing
- Medicare Appeals Council review
- Federal District Court
Most denials that get reversed are resolved at the first or second level, which is why submitting complete medical records and a clear letter of medical necessity with the initial reconsideration matters. You do not have to handle this alone. State Health Insurance Assistance Programs (SHIPs), federally funded counseling services that offer free, unbiased Medicare guidance in every state, can help you prepare and file an appeal at no cost. You can find your state's SHIP through Medicare.gov's claims and appeals page or directly at shiphelp.org.
Key Takeaway
A prior authorization denial is not the end of the process. Free SHIP counselors can help you build an appeal, and the first step, reconsideration by the plan, is often where additional documentation from your doctor makes the difference.
Helpful next step
See how prior authorization rules and other trade-offs differ across Medicare Advantage, Original Medicare, and Medigap.
Learn More
Talk with Medicare Plan Path for plain-language guidance on how prior authorization could affect your plan choice.