Prior authorization in Medicare Advantage

How it works

Usually your doctor submits the request, with medical records supporting it. The plan's Evidence of Coverage lists which services need prior authorization. Plans must follow Original Medicare's coverage rules when deciding whether something is medically necessary.

Protections CMS requires

• An approval for a course of treatment must stay valid for as long as it's medically necessary, rather than being reapproved piece by piece.
• If you're new to a plan and already in treatment, the plan must give you a transition period of at least 90 days before requiring new approval.
• Denials based on medical necessity must be reviewed by a doctor or other appropriate professional.
• Plans must make decisions within set timeframes, faster for urgent requests.

If a request is denied

You have the right to appeal. Ask the plan for a written explanation, work with your doctor, and request a reconsideration within the deadline in the denial notice. If waiting could seriously harm your health, ask for a fast (expedited) decision. If the plan upholds the denial, the case goes to an independent reviewer automatically.

Original Medicare and the WISeR model

Original Medicare generally doesn't use prior authorization. From January 1, 2026, CMS is testing it for a limited list of services, such as certain nerve stimulator implants, skin substitutes and knee arthroscopy for osteoarthritis, in six states: Arizona, New Jersey, Ohio, Oklahoma, Texas and Washington. Providers can choose prior authorization or have the claim reviewed before payment.