Since their introduction over 20 years ago, Medicare Advantage plans have become a rapidly expanding option in the Medicare system. In 2025, more than 34 million people enrolled in a Medicare Advantage plan, accounting for 54% of those eligible for Medicare, KFF reports. By 2034, 64% of all eligible beneficiaries of Medicare are expected to be enrolled in a Medicare Advantage plan.
Medicare Advantage plans, administered by private companies, are required to offer comparable coverage to original Medicare, which consists of Part A (hospital insurance) and Part B (medical insurance). Many Medicare Advantage plans, however, also come with extra benefits that original Medicare does not provide, such as prescription drug coverage, vision and dental care and gym memberships.
One potential drawback of Medicare Advantage plans is their use of prior authorizations when determining if care is medically necessary. If a service or procedure is deemed medically unnecessary, your Medicare Advantage plan can deny coverage.
Here’s what to do if your Medicare Advantage plan refuses to provide coverage.
[READ: Worst Medicare Advantage Plans: How to Find a Good One]
What Is Prior Authorization?
Prior authorization is a process in which a health care provider must receive approval from a patient’s insurance plan before it will cover a specific medication, procedure or treatment. While prior authorization is intended to reduce unnecessary care and control costs, critics warn that prior authorization can delay or deny medically necessary treatment.
Nearly all Medicare Advantage enrollees are required to obtain prior authorization for at least some services, such as:
— Certain prescription medications
— Chemotherapy or radiation treatments
— Imaging tests, such as MRIs or CT scans
— Physical, occupational or speech therapy
— Specialist visits
How often do Medicare Advantage plans deny prior authorization requests?
Medicare Advantage plans fully or partially denied 3.2 million of the 50 million prior authorization requests submitted in 2023, according to KFF. Only about 11% of denials were appealed, but nearly 82% of them were overturned.
Researchers analyzing claims from a large insurer found that in 2022 about one-third of Medicare Advantage enrollees experienced at least one service denial each year. Roughly 15% of prior authorization denials were tied to Medicare Advantage policies that were more restrictive than original Medicare, indicating that some denied care would have been covered under original Medicare. The Office of the Inspector General reached a similar conclusion, finding that 13% of Medicare Advantage coverage denials met original Medicare criteria. In response to these findings, the Centers for Medicare & Medicaid Services (CMS) issued a final rule clarifying that Medicare Advantage coverage may not be more restrictive than original Medicare.
Can AI deny my Medicare Advantage claim?
AI alone cannot deny your Medicare Advantage claim. AI tools may be used to support reviews, but coverage decisions must also include clinician oversight.
According to a CMS final rule issued in 2023, Medicare Advantage plans also “must ensure that they are making medical necessity determinations based on the circumstances of the specific individual, as opposed to using an algorithm or software that doesn’t account for an individual’s circumstances.”
Further changes are on the horizon, such as the Improving Seniors Timely Access to Care Act, reintroduced in 2025 and currently pending in Congress. This act aims to streamline prior authorization processes in Medicare Advantage plans and reinforce regulations issued by CMS. It also includes further guardrails intended to limit inappropriate reliance on AI or automated decision-making in coverage determinations.
Reasons for Denial
There are many reasons why a prior authorization may be denied, including:
— Administrative errors. Sometimes there can be mistakes or incomplete information, such as missing codes in the submitted paperwork or an error in processing the request.
— Benefit exhaustion. The enrollee has exhausted their benefits for the year, such as hitting the maximum out-of-pocket limit or coverage limit for a particular service.
— Insufficient documentation. The submitted request did not include enough information or documentation to support the claim of medical necessity.
— Lack of medical necessity. The plan determines that the requested service or medication is not medically necessary.
— Lack of FDA approval. The treatment or medication has not been approved by the Food and Drug Administration for the specific condition being treated.
— Out-of-network providers or facilities. Many plans require enrollees to use in-network providers or facilities only.
How to Appeal a Denial
Appealing a denial can be frustrating and time-consuming, but it may be worth the effort in the end.
“Most people don’t bother to appeal denials, but we urge people to do so,” explains David Lipschutz, the co-director and attorney for the Center for Medicare Advocacy in Washington, D.C. “Your chances of winning are generally better after the first couple levels of appeal.”
Before you begin, carefully read the denial letter and note any questions or concerns you have. At each level, a set of instructions on how to move the appeal to the next level should be included with the decision letter.
Call your plan to review the denial and to confirm that it wasn’t issued because of something easily resolvable, such as missing or incomplete information or an administrative error.
If you still feel that an appeal is warranted, Medicare’s appeal process has five levels:
— Level 1: Reconsideration. You will need to begin the process through your Medicare Advantage plan. You, your representative or your doctor must appeal within 65 days of the coverage determination. If you miss the deadline, you must include the reason for filing late in your appeal.
— Level 2: Review by an Independent Review Entity (IRE). If your appeal is denied, you have the right to request a review by an independent third party that works for Medicare, not your insurance plan.
— Level 3: Decision by the Office of Medicare Hearings and Appeals. If the IRE upholds the denial, you have the right to request a hearing before an administrative law judge (ALJ) or to have them decide without a hearing based on the information in your appeal record. Hearings are typically held by phone or video teleconference.
— Level 4: Medicare Appeals Council review. If the ALJ denies the appeal, you have the right to request a review by the Medicare Appeals Council.
— Level 5: Judicial review by a federal-district court. For your appeal to move forward to this final level, the appeal must meet the minimum amount of $1,960 in 2026.
Medicare Advantage appeals have two response times: standard and expedited. The plan has to respond in writing within 30 calendar days for a standard request and within 72 hours for an expedited request. Different response times for each level of appeal must be met, and a useful chart outlining response times can be found at Medicare.gov.
[READ: How to Use AI to Help Fight a Health Insurance Denial: Step-by-Step Guide]
Helpful Tips
Experts recommend adopting these tips to strengthen your appeal:
— Keep detailed records. Keep a file with all of the paperwork from every appeal level sent to you. Keep a detailed account of any phone calls with your insurance plan, including dates, times and what was said.
— Be repetitive. Even if you think they should already have it, ensure you provide your name, address, Medicare number, the service being appealed and why in all correspondence.
— Understand your rights. Familiarize yourself with your rights under Medicare and your Medicare Advantage plan. Lipschutz advises researching your plan’s coverage rules, making sure you understand what criteria must be met to better prepared to argue your case.
— Be persistent. Don’t give up if your appeal is denied at first. You may need to appeal multiple times to be successful.
[READ: When and How to Change Your Medicare Plan]
Bottom Line
Prior authorizations can decrease wasteful spending but also create barriers to care. If you feel your Medicare Advantage plan inappropriately denied your request, you should feel empowered to appeal. Understanding why your request was denied, keeping thorough records and staying persistent through the appeals process can be critical to accessing the care you need.
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What to Do When Medicare Advantage Plans Deny Coverage originally appeared on usnews.com
Update 01/16/26: This story was previously published at an earlier date and has been updated with new information.