Medicare denied your claim — or paid far less than you expected — and now you're staring at a bill you shouldn't owe. The Medicare appeals process is formal, time-sensitive, and layered across five distinct levels, but it's also one of the strongest consumer protections in U.S. healthcare. Understanding exactly how to navigate each step dramatically increases your chances of getting the decision reversed.

What Are Your Rights When Medicare Denies a Claim?

Medicare beneficiaries have a federally guaranteed right to appeal any coverage or payment decision. This right applies whether you have Original Medicare (Parts A and B), a Medicare Advantage plan (Part C), Medicare Part D prescription drug coverage, or a Medicare Supplement (Medigap) policy. The legal basis for this right comes from the Social Security Act, and the process is administered through the Centers for Medicare & Medicaid Services (CMS).

When Medicare denies a claim or reduces a payment, you will receive one of two key documents:

  • Medicare Summary Notice (MSN): Sent quarterly to Original Medicare beneficiaries. It lists services billed, what Medicare paid, what you owe, and the reason for any denial.
  • Explanation of Benefits (EOB): Sent by Medicare Advantage or Part D plans, typically within 30 days of a claim decision.

Read the denial reason carefully — it will be listed as a remark code or short explanation. Common denial reasons include "not medically necessary," "benefit exhausted," "service not covered," and "missing or invalid information." The denial reason determines your best argument on appeal.

What Are the Five Levels of the Medicare Appeals Process?

Medicare's appeal structure has five formal levels. You must generally exhaust each level before advancing to the next, and each level has its own deadline, decision-maker, and monetary threshold.

  1. Level 1 — Redetermination: Filed with your Medicare Administrative Contractor (MAC) for Original Medicare, or directly with your Medicare Advantage or Part D plan. Deadline: 120 days from the date on your MSN or EOB. The MAC or plan must respond within 60 days.
  2. Level 2 — Reconsideration: Reviewed by a Qualified Independent Contractor (QIC), a third party with no financial stake in the outcome. Deadline: 180 days from the Level 1 decision. The QIC has 60 days to respond. For Part D, this step goes to an Independent Review Entity (IRE).
  3. Level 3 — ALJ Hearing: An Administrative Law Judge (ALJ) hearing through the Office of Medicare Hearings and Appeals (OMHA). You can request this in person, by video, or on the record (written only). Deadline: 60 days from the Level 2 decision. Monetary threshold required: $180 (2024). If your dispute doesn't meet this amount, you cannot proceed to Level 3.
  4. Level 4 — Medicare Appeals Council: Review by the Departmental Appeals Board (DAB) Medicare Appeals Council. Deadline: 60 days from the ALJ decision. No additional monetary threshold is required at this level.
  5. Level 5 — Federal District Court: Judicial review in U.S. District Court. Deadline: 60 days from the Appeals Council decision. Monetary threshold required: $1,840 (2024). This is rare but available when all other levels have failed.

Missing a deadline forfeits your appeal rights at that level unless you can show "good cause" for the delay — for example, a serious illness or a natural disaster. Document any good-cause reason in writing when submitting late.

How Do You File a Medicare Redetermination (Level 1 Appeal)?

The redetermination is where most billing disputes are resolved. Here's how to file it correctly:

  1. Obtain Form CMS-20027 (the Medicare Redetermination Request Form) from CMS.gov, or write a letter that includes all required information: your name, Medicare Beneficiary Identifier (MBI), the specific claim number(s) being appealed, the date of service, the item or service in dispute, and a clear statement that you are requesting a redetermination.
  2. Gather supporting documentation. This is critical. Attach your MSN or EOB, any relevant medical records, physician letters of medical necessity, discharge summaries, or operative notes. A letter from your treating physician specifically addressing the denial reason carries significant weight.
  3. Identify the correct MAC. Your MSN or denial notice will name your MAC. Common MACs include Novitas Solutions, CGS Administrators, WPS Government Health Administrators, and Palmetto GBA. Submit to the address listed on your denial notice — not CMS directly.
  4. Send via certified mail with return receipt. Keep copies of everything you submit. Note the tracking number and the date of mailing as your proof of timely filing.
  5. Follow up at 30 days. MACs are required to issue a decision within 60 days. If you haven't received a response, call the MAC directly or contact 1-800-MEDICARE.

How Do You Write a Strong Medicare Appeal Letter?

Your appeal letter is your argument — treat it like a legal brief, not a complaint. A weak letter says "I disagree with this decision." A strong letter says exactly why Medicare's denial is incorrect under its own rules.

Structure your letter as follows:

  • Header: Beneficiary name, MBI, claim number, date of service, name of MAC or plan.
  • Statement of dispute: "I am requesting a redetermination of the denial of [specific service] rendered on [date], Claim No. [XXXXXXXXXX], denied for reason: [reason code/explanation]."
  • Clinical argument: Cite specific Medicare coverage policies. If the denial was "not medically necessary," reference the relevant Local Coverage Determination (LCD) or National Coverage Determination (NCD) — both are searchable on the CMS Coverage Database. Show how your condition meets the stated criteria.
  • Regulatory argument: If the denial involves a procedural or coding error, identify the specific CPT or HCPCS code in dispute and explain the correct coding supported by documentation.
  • Request: Close with a clear, specific demand: "I request that Medicare reverse this denial and approve payment for [service] in full."

Attach a physician's letter of medical necessity that directly addresses the LCD or NCD criteria — ideally written in the physician's own words, not a generic template. Reviewers recognize and discount templated letters.

What Happens If You Have a Medicare Advantage Plan Instead of Original Medicare?

Medicare Advantage (Part C) appeals follow a parallel but distinct process, governed by CMS rules but administered by private insurers. Key differences include:

  • Prior authorization denials require an organization determination before you can appeal. Request this in writing from your plan before or after service.
  • Expedited appeals are available when your health could be seriously harmed by waiting. Plans must respond to expedited requests within 72 hours (coverage decisions) or 24 hours (payment decisions). Submit a written request marked "EXPEDITED" and have your physician note that a delay would be detrimental.
  • If your plan upholds its denial at the reconsideration level and the disputed amount is $180 or more, the case is automatically sent to a CMS-contracted Independent Review Entity (IRE) — you don't need to file again.
  • For hospital discharge disputes, use the Immediate Advocate Review process through your Beneficiary and Family Centered Care Quality Improvement Organization (BFCC-QIO). This can temporarily halt a discharge while your case is reviewed.

How Do You Track a Medicare Appeal and Know If You're Winning?

Medicare provides an online tool called the Medicare Appeals Status portal, accessible through MyMedicare.gov. You can check the status of appeals at Levels 1 through 3 using your appeal tracking number, which is assigned when your MAC or plan receives your request.

Indicators that your appeal is progressing well include: requests for additional documentation (respond quickly and completely), assignment of an ALJ hearing date, and written acknowledgment letters from each review body. A favorable decision will specify the claim number, the reversed denial, and direct the payer to reprocess payment. An unfavorable decision will explain the reasoning and state your rights to advance to the next level — read this section carefully before deciding whether to escalate.

If you win at any level, confirm that the claim is actually reprocessed and paid. Call the MAC or your plan 30 days after a favorable decision if you haven't seen updated payment on your MSN or EOB. Favorable decisions don't always trigger automatic reprocessing without a follow-up.

Frequently Asked Questions

A Level 1 redetermination must be decided within 60 days of the MAC receiving your request. A Level 2 QIC reconsideration adds another 60 days. If you reach an ALJ hearing at Level 3, current processing times can run several months to over a year due to backlog at OMHA, though the statutory requirement is 90 days. Expedited appeals for urgent medical situations have much faster turnaround — as few as 24 to 72 hours for Medicare Advantage plans.

Yes. A provider, physician, or authorized representative can file an appeal on your behalf, but you must sign a written Appointment of Representative form (CMS-1696) authorizing them to act for you. Without this form, the MAC or plan may not share claim information or accept filings from a third party. Keep a copy of the signed CMS-1696 and attach it to every appeal submission.

A Local Coverage Determination (LCD) is a Medicare Administrative Contractor's written policy defining when a specific service is considered medically necessary and therefore covered in that geographic region. When Medicare denies a claim as "not medically necessary," the LCD is often the governing standard — and your appeal must show that your diagnosis and clinical circumstances meet the LCD's listed criteria. LCDs are publicly searchable on the CMS Coverage Database at cms.gov, and citing the specific LCD number in your appeal letter demonstrates that you've engaged with the actual standard being applied.

While your appeal is pending, providers and hospitals are generally prohibited from sending a Medicare-covered balance to collections, provided you have notified them in writing that you have filed an appeal. Request a billing hold in writing when you file, and keep proof of delivery. However, amounts that are definitively your responsibility — such as your deductible or co-insurance — are not suspended by an appeal and may still be pursued.

You can still file a late appeal if you have "good cause" for the delay. Good cause includes circumstances such as serious illness, a death in the family, destruction of records due to a natural disaster, or failure to receive the denial notice. Submit your appeal with a separate written explanation of the good cause reason and any supporting documentation, such as a physician's note or a FEMA disaster declaration. The MAC or review body will determine whether good cause is sufficient, so be specific and thorough rather than vague.