Medicare Advantage Prior Authorization Denied: How to Appeal" class="auto-link">Prior Authorization Denied — Your Federal Rights

Prior authorization (PA) is one of the most controversial tools Medicare Advantage plans use. Unlike Original Medicare, which rarely requires PA for covered services, MA plans can — and do — require prior approval before covering many types of care. When that approval is denied, your health and finances are directly affected.

But federal law is clear: you have the right to appeal every prior authorization denial. The CMS 2024 Final Rule significantly strengthened those rights. Here's what you need to know.

Why Medicare Advantage Uses Prior Authorization More Than Original Medicare

Original Medicare pays for covered services on a fee-for-service basis with minimal preauthorization requirements. Medicare Advantage plans, by contrast, are paid a fixed monthly amount per enrollee by CMS and bear the financial risk for the care their members use. This creates an incentive to manage utilization through PA.

While prior authorization can serve legitimate clinical purposes, research and CMS audits have consistently found that MA plans sometimes use PA to delay or deny medically necessary care — care that Original Medicare would have covered without question.

The CMS 2024 Final Rule: Stronger PA Protections

Effective in 2024, CMS implemented rules that significantly tightened MA prior authorization requirements:

• Decision timelines: MA plans must issue urgent PA decisions within 72 hours and standard PA decisions within 7 calendar days.
• Continuity of care: When a patient transitions between care settings or changes MA plans, plans must honor existing PA approvals for at least 90 days to allow continuity of treatment.
• Clinical criteria: Plans must use prior authorization criteria consistent with Original Medicare coverage standards. Plans may not apply more restrictive criteria than CMS policy allows.
• Transparency: Plans must make their PA criteria publicly available.

If your MA plan violated any of these requirements, that violation is grounds for both an appeal and a CMS complaint.

Common Reasons MA Plans Deny Prior Authorization

PA denials typically fall into several categories:

• Not medically necessary: The plan's clinical reviewer determined the service doesn't meet the plan's criteria.
• Service not covered under the plan: The service is excluded from your specific plan's benefits.
• Insufficient documentation: The PA request didn't include adequate clinical documentation.
• Step therapy: The plan requires you to try less expensive alternatives first.
• Out-of-network provider: For HMO plans, PA may be denied because the requested provider isn't in the network.
• Wrong level of care: The plan believes a less intensive setting would be appropriate.

Step 1 — Request an Expedited PA Decision

If your health condition is urgent, you are entitled to request an expedited prior authorization decision. Under the 2024 CMS rules, the plan must respond within 72 hours. To request expedited review, your doctor should state clearly in the PA request that a delay would seriously jeopardize your health. The plan cannot require this be in any particular form.

Step 2 — Peer-to-Peer Review

Before or alongside a formal appeal, your physician can request a peer-to-peer review — a direct conversation with the plan's medical director. This is one of the most effective early steps. Many PA denials are based on incomplete information, and a physician-to-physician conversation can resolve them without a formal appeal.

Peer-to-peer requests generally must be made within a short window of the PA denial notice. Ask your doctor's office to act promptly.

Step 3 — Level 1 Plan Appeal

If the PA remains denied, file a formal Level 1 appeal with your MA plan. Your Level 1 appeal should include:

• The original PA denial notice
• A detailed letter of medical necessity from your physician
• Clinical records supporting the need for the requested service
• A written argument explaining why the denial is inconsistent with Original Medicare coverage standards
• Reference to the CMS 2024 Final Rule requirements if the plan violated PA timelines

The plan must issue its Level 1 decision within the same 72-hour (expedited) or 7-day (standard) timeframes that apply to the original PA request.

Step 4 — Level 2 External Independent Review: Complete Guide" class="auto-link">External Review (MAXIMUS)

If the plan upholds the denial at Level 1, you escalate to MAXIMUS Federal Services, CMS's independent external review organization for Medicare Advantage. MAXIMUS applies Original Medicare coverage standards — not the plan's proprietary criteria.

MAXIMUS must decide within:

• 72 hours for expedited requests
• 60 days for standard requests

Instructions for requesting MAXIMUS review will be in your Level 1 denial letter.

File a CMS Complaint for Timeline Violations

If your MA plan failed to issue a PA decision within the required timeframes — 72 hours for urgent, 7 days for standard — that is a violation of CMS rules. File a complaint at medicare.gov or call 1-800-MEDICARE (1-800-633-4227). CMS can and does sanction plans that habitually violate PA timelines.

Continuity of Care Protections

If you recently changed MA plans or transitioned from one care setting to another and your new plan is denying PA for ongoing treatment, invoke the continuity of care rule. Under the 2024 CMS Final Rule, MA plans must cover ongoing treatment under existing PA approvals for at least 90 days following a plan transition. This protection is especially important for patients receiving chronic disease management, cancer treatment, or mental health care.

Get Free Help from SHIP

State Health Insurance Assistance Programs (SHIP) provide free counseling for Medicare beneficiaries and can help you navigate PA appeals at no cost. Call 1-800-MEDICARE (1-800-633-4227) to reach your state SHIP counselor.

Fight Back With ClaimBack

A Medicare Advantage prior authorization denial is not a dead end. Federal rules give you real recourse — and ClaimBack helps you use it effectively, from your first appeal through external review.

Start your free appeal →

Related Reading

• What Is Medical Necessity?
• Internal vs. External Insurance Appeal
• Common Reasons Insurance Claims Are Denied