Dispute a Medicare Claim in 180 Days: Your Complete Guide

Most people who get a Medicare denial letter assume the decision is final. It isn’t. And that assumption costs beneficiaries real money every single year.

Here’s a number that stopped me cold when I first saw it: according to data from the Office of Medicare Hearings and Appeals (OMHA), beneficiaries who appeal Medicare denials win their cases at the Administrative Law Judge level roughly 75% of the time. Three out of four. That means the initial denial, which feels so official and intimidating in that envelope, is often just… wrong. Or at least contestable. And most people never push back.

I’ve sat across the table from hundreds of people over the years who quietly absorbed a denial, paid the bill, and moved on. I understand why. The letters are full of codes and jargon, and when you’re also managing a health condition, fighting paperwork feels like one burden too many. But if there’s one thing I want you to take from this article, it’s that the appeals process was specifically built for you, and it works more often than anyone tells you.

What You’re Actually Disputing (and Why the Terminology Matters)

Before we get into the how, let’s make sure we’re talking about the same thing. A Medicare “claim dispute” or “appeal” is your formal request for Medicare to reconsider a coverage or payment decision. That decision might be a denial of a service, a determination that something isn’t “medically necessary,” or a bill you received that you think Medicare should have paid.

The document you’ll need first is your Medicare Summary Notice, or MSN. If you’re in Original Medicare (Parts A and B), this mailed statement arrives every three months and lists every service billed to Medicare on your behalf, what Medicare paid, and what you owe. Think of it as your receipt. If you’re in a Medicare Advantage plan (Part C), the equivalent is called an Explanation of Benefits, or EOB. Different name, same idea. I’ve had people call me convinced they don’t have this document, and it’s usually sitting in a pile of mail they assumed was junk. Open everything with a Medicare logo on it.

One thing that trips people up: you can dispute a denial before you’ve even received a bill. If your doctor says a service might not be covered, you can request an “Advance Beneficiary Notice” (ABN) and, in some cases, ask Medicare to review it preemptively. This is called an “organization determination” for Advantage plans, and most people don’t know it exists.

The Five Levels of Appeal

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The Medicare appeals process is structured in five levels, each escalating if the previous one doesn’t go your way. Most disputes resolve in the first two. Here’s how they look in practice:

A few things worth knowing that aren’t obvious from the table: Level 3 (the ALJ hearing) has a minimum dollar threshold, currently $180 for Part B and $180 for Part A disputes (these amounts adjust annually, so verify the current figure at Medicare.gov). Below that threshold, you can’t request an ALJ hearing. Also, at Level 3, you can often request an on-the-record review instead of an in-person hearing, which is faster and doesn’t require travel. I almost always recommend that for straightforward cases.

How to Actually File the Dispute: Step by Step

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This is where I want to get specific, because the generic advice out there is often vague to the point of uselessness.

Step 1: Get your MSN or EOB and find the claim in question. The MSN shows a claim number, the service date, what was billed, and the reason code for the denial. Write down that reason code. It matters.

Step 2: Request your medical records from your provider. You want documentation showing the service was medically necessary. Your doctor’s notes, test results, referral letters. If your doctor believes the service was appropriate, ask them to write a supporting letter. This single step, getting a letter from your physician, dramatically improves your odds at Level 1.

Step 3: Fill out the right form. For Part B redeterminations, that’s CMS Form 20027. For Part A, it’s often a written request. You can find current forms at the Centers for Medicare & Medicaid Services website. Write clearly, include your Medicare number, the claim number, the date of service, and a brief explanation of why you believe the denial was wrong. Brief. A page is enough.

Step 4: Send it certified mail, return receipt requested. Keep a copy of everything. I’ve seen people lose appeals simply because they couldn’t prove they filed within the deadline. That green return-receipt card is your proof.

Step 5: Wait, and follow up. Level 1 decisions should come within 60 days. If you haven’t heard back, call 1-800-MEDICARE (1-800-633-4227) and ask about the status.

One scenario I’ve seen go well: A woman in her early 70s, let’s call her Maria, had a home health aide visit denied as “not medically necessary” following a hip replacement. She had her surgeon write a one-page letter explaining exactly why homebound status applied under Medicare’s criteria. Filed Level 1 redetermination. Result: full denial reversed within 45 days, approximately $1,200 in charges dropped.

Another: A man disputing a skilled nursing facility discharge got his case to Level 3. The ALJ agreed with him. He stayed in the facility an additional 11 days, covered by Medicare. That was roughly $4,400 in coverage he would have lost had he accepted the original decision.

The “Medically Necessary” Problem

Honestly, this is the source of most denials I see. Medicare uses a specific definition: a service is medically necessary if it’s “reasonable and necessary for the diagnosis or treatment of illness or injury.” Sounds clear. It isn’t.

Medicare contractors, who are private companies paid by the government to process claims, sometimes apply Local Coverage Determinations (LCDs) that are stricter than what your doctor ordered. The Centers for Medicare & Medicaid Services publishes all LCDs publicly. I’d encourage you to look up the LCD for whatever service was denied, because sometimes the denial is based on missing documentation rather than the service itself being uncovered. That’s actually good news, because it means adding the right documentation can reverse the denial at Level 1 without a fight.

That jump at Level 3 is striking, and it’s consistently documented in OMHA’s annual reports. Independent ALJs, who aren’t employed by Medicare contractors, review the evidence fresh. They overturn contractor decisions at a rate that should make every denial feel provisional, not permanent.

Get Help: You Don’t Have to Do This Alone

If reading all of this makes you feel like you need a law degree, I want to reassure you: you don’t. The State Health Insurance Assistance Program (SHIP) offers free one-on-one counseling in every state, from trained volunteers who know this process cold. They can review your denial letter with you, help you draft your appeal, and tell you if your case is strong. In my experience, people who use SHIP counselors file better appeals. Not because SHIP writes the appeal for you, but because they help you frame the argument in Medicare’s language.

You can also hire a Medicare attorney, though for most Part B disputes, the amounts involved don’t justify legal fees unless you’ve reached Level 3 or beyond. At that point, some attorneys work on contingency.

One thing I’ll admit I got wrong for years: I used to tell people to just call Medicare first before filing a formal appeal. I thought it might resolve faster. It almost never does. A phone call doesn’t stop the clock on your appeal deadline, and it rarely changes a contractor’s decision. File the formal appeal. You can call too, but file.

Sources

• Office of Medicare Hearings and Appeals (OMHA) Annual Report: Annual statistics on Medicare appeal volumes and overturn rates by level.
• Centers for Medicare & Medicaid Services (CMS) Appeals Overview: Official guidance on the five-level appeals process, forms, and timelines.
• State Health Insurance Assistance Program (SHIP) National Network: Free counseling resource for Medicare beneficiaries navigating disputes and appeals.
• Medicare.gov: How to Appeal a Medicare Decision: Plain-language walkthrough of beneficiary appeal rights (current as of July 2026).
• Medicare Interactive (Medicare Rights Center): Nonprofit-produced resource with detailed appeal guidance, especially for Part C and Part D denials.

Photo: Kampus Production via Pexels

This article is for informational purposes only. Medicare rules change annually. Always verify current plan details at Medicare.gov or by calling 1-800-MEDICARE (1-800-633-4227). This site does not sell insurance or recommend specific plans.

Recommended Resources

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• Medicare For Dummies (~$22), The definitive consumer guide to Medicare, enrollment windows, Part A/B/C/D, and supplement plans.
• Get What’s Yours for Medicare (~$17), Maximize your Medicare benefits and minimize out-of-pocket costs. Covers Part D drug coverage gaps and Medigap in depth.