Introduction
New to Medicare? Start with Medicare basics for Parts A–D and how enrollment fits together.
Medicare Advantage (Medicare Part C) covers tens of millions of people—and generates a large share of denial and appeal work for advocates. The plan card may look like commercial insurance, but the appeals path is Medicare's, not a typical state insurance external review.
This guide explains what Medicare Advantage is, how it differs from Original Medicare, who oversees it, and how appeals and grievances usually work at a beginner level. For employer or Marketplace coverage, use the other plan-type guides instead.
What Medicare Advantage is
What it is
Medicare Advantage is a way to receive Medicare benefits through a private plan that contracts with the federal government. Instead of the government paying providers under Original Medicare (Parts A and B), Medicare pays the plan a set amount to cover enrollees. The plan must provide at least the same Medicare benefits, and often adds extras like dental or vision—sometimes with tighter networks and more prior authorization.
How it differs from Original Medicare
Under Original Medicare, you can see any Medicare provider (with usual cost-sharing) and buy a separate Part D drug plan or Medigap supplement. Under Medicare Advantage, you generally use the plan's network, follow referral and prior auth rules, and get drugs through the plan's Part D benefit if included. Appeals go through the Medicare Advantage organization (MAO) and Medicare appeal levels—not the same forms as a Marketplace plan.
How enrollment works
People enroll during Initial Enrollment Period, Annual Enrollment Period (October 15–December 7), or Medicare Advantage Open Enrollment (January 1–March 31) in many cases, with other special periods. The patient's red, white, and blue Medicare card still exists, but day-to-day claims run through the MA plan card. Keep both numbers in the file.
How it works
Plans and CMS contracts
Each Medicare Advantage plan is a Medicare Advantage Organization (MAO) with a federal contract. CMS sets rules for marketing, benefits, quality, appeals, and coverage standards. The plan must follow Medicare law and CMS guidance even when it uses a commercial insurer brand.
Networks, prior authorization, and denials
MA plans often require primary care referrals and prior authorization for specialists, imaging, procedures, and inpatient care. Denials may say not medically necessary, not covered, out of network, or prior auth not obtained. The clinical story matters, but so does whether network and authorization rules were met.
Drug coverage (Part D)
Most MA plans include Part D drug coverage. Pharmacy denials involve formulary tiers, step therapy, and quantity limits—similar advocacy themes to commercial plans but with Medicare appeal rights. Stand-alone Part D plans (without Advantage) follow related Medicare appeal rules; this guide focuses on integrated MA-PD plans.
Who regulates and oversees
CMS (Centers for Medicare & Medicaid Services)
CMS is the primary federal regulator for Medicare Advantage. CMS oversees plan compliance, benefit administration, marketing, and the Medicare appeals system. Beneficiaries can file grievances and complaints with the plan and with Medicare. See CMS: Medicare and official Medicare appeal materials at Medicare.gov claims and appeals.
What state insurance departments usually do
State insurance departments generally do not decide Medicare Advantage benefit appeals the way they do for fully insured commercial plans. States may still regulate some insurer conduct, licensing, or agent behavior, but the Medicare appeal path is federal. Do not file only a state external review form and assume it replaces Medicare steps.
Other help
State Health Insurance Assistance Programs (SHIPs)offer free Medicare counseling in every state. Beneficiaries can also use Medicare's 1-800-MEDICARE line. Legal services organizations sometimes help with ALJ-level appeals and beyond.
Appeals and complaints
Medicare appeal levels (simplified)
Medicare uses a staged system. Names and forms can vary slightly, but the flow is generally:
- Request for redetermination—appeal to the plan (often within 60 days of the denial or Medicare notice; confirm dates on the letter).
- Reconsideration—if unfavorable, appeal to the Qualified Independent Contractor (QIC) level.
- Administrative Law Judge (ALJ) hearing—if amount in controversy and other requirements are met.
- Medicare Appeals Council review.
- Federal court—rare for advocates without attorney support.
Always use the dates and forms on the patient's notice. Build the packet with Building a strong appeal packet and clinical support from treating providers.
Fast (expedited) appeals
When standard time could seriously harm health, request an expedited (fast) appeal. Document why waiting is dangerous. The Appeals Roadmap explains the urgency framing; Medicare has its own expedited rules and timeframes.
Grievances
A grievance addresses quality of care, customer service, or process problems—not always a specific claim line. Beneficiaries can file grievances while also appealing denials. Poor access to in-network providers or repeated lost paperwork may support a grievance plus a complaint to Medicare.
CMS complaints
When the plan mishandles appeals, misleads members, or violates Medicare marketing rules, a CMS or Medicare complaint may help. That is separate from winning a medical necessity appeal on the merits. See Complaints to regulators.
Advocate playbook
Red flags
- Plan tells the patient to use state insurance external review for a Part C denial
- Missing Medicare number or wrong appeal form (commercial form instead of CMS form)
- Failure to offer expedited review when inpatient or urgent care is at stake
- Network adequacy issues framed only as "provider choice" without documenting access barriers
Practical tips
- Confirm Medicare Advantage (Part C) on card and in CMS records—not just "Medicare."
- Calendar Medicare-specific deadlines from each notice.
- Connect with SHIP for form help and state-specific counseling.
- Cite Medicare coverage rules and plan policy; include physician letters for clinical denials.
- Keep grievance and appeal tracks separate but documented in one timeline.
Bottom line
Medicare Advantage is Medicare delivered through private plans under federal rules. Appeals follow the Medicare ladder, not typical state commercial insurance external review. CMS and Medicare.gov resources—not state DOI benefit appeals—are the core oversight path. Build a strong clinical record, hit Medicare deadlines, and use SHIP and CMS complaints when the process itself fails.