Medicare Claim Appeal: How to Challenge a Denial, Step by Step

If Medicare or your health plan denied a claim, you can appeal, and the first step is to find out which kind of coverage made the decision. With Original Medicare, you have 120 days from receiving your Medicare Summary Notice (MSN) to request a redetermination. With a Medicare Advantage or Part D plan, you generally have 65 days from the date on the denial notice to ask the plan to reconsider. Most denials never get past that first level because people miss the window, send the request to the wrong place, or file without any new evidence from their doctor.

This guide covers the full process: who decides at each level, the deadlines, the forms, the dollar thresholds, and what actually moves a denial. It also covers a few things that surprise families, such as why calling 1-800-MEDICARE will not overturn a decision.

TL;DR

• Find your coverage type first. Original Medicare appeals go through a Medicare Administrative Contractor. Medicare Advantage and Part D appeals start with your own plan.
• Watch the clock. Original Medicare gives you 120 days from receiving the MSN. Advantage and Part D plans give you 65 days from the date of the denial notice.
• Get your doctor involved before you file. A letter of medical necessity or updated clinical notes often decides a first-level appeal.
• Ask for a fast appeal if waiting could harm your health. Expedited decisions come back in 72 hours for most services, or 24 hours for Advantage Part B drugs.
• Families need paperwork. To act for a relative, you need a signed Appointment of Representative form, not just their verbal permission.

Table of Contents

• Start by reading the notice, not filling out a form
• The five levels of Medicare appeal
• Original Medicare: how to file a redetermination
• Medicare Advantage and Part D: your plan decides first
• When you cannot wait: fast appeals
• What actually strengthens an appeal
• Common mistakes that sink appeals
• Helping a parent or spouse with an appeal
• Premium disputes are a different appeal
• Our perspective: most denials are a gap that someone could have seen coming
• Free help with your appeal
• FAQ
• Sources

Start by reading the notice, not filling out a form

Every appeal starts with a document that says “no.” For Original Medicare, that is usually the Medicare Summary Notice, mailed quarterly and also available in your online Medicare account. For a Medicare Advantage plan, it is a denial letter or an Explanation of Benefits from the plan. For a drug plan, it is a coverage determination notice, often handed to you at the pharmacy counter before you ever see a letter.

Before doing anything else, look for three things on that notice:

1. The date of the notice. Your deadline runs from it, or from when you received it, depending on the plan type (more below).
2. The stated reason for denial. “Not medically necessary,” “service not covered,” “out of network” and “prior authorization not obtained” are different problems with different fixes.
3. Where to send the appeal. The notice names the contractor or plan and explains how to file. Follow those instructions, because Medicare says you will get a decision letter at every level with directions for moving to the next one, as laid out on its Original Medicare appeals page.

It helps to ask your provider’s billing office to double-check the claim. Sometimes the denial is a coding error or a missing detail, and a corrected claim is faster than an appeal. Medicare’s own appeals booklet suggests asking your provider whether they can help before you begin, which you can see in the Medicare Appeals publication.

The five levels of Medicare appeal

The structure is the same on paper for every type of coverage, though the names and deadlines shift. CMS describes five levels of appeal: a first decision by the contractor or plan, an independent review, an administrative law judge (ALJ) hearing, review by the Medicare Appeals Council, and finally federal court. If you disagree with the result at one level, you can usually go to the next.

The dollar thresholds, called the amount in controversy, are the 2026 figures from the CMS appeals flowchart. They are adjusted every year, so check the current figure if you are reading this later. One useful detail: you can often combine several related denied claims to reach a threshold, rather than assuming each denied service must clear it alone.

Realistically, most people resolve their dispute at level 1 or 2. The upper levels exist, but they take much longer and are rarely worth pursuing without strong documentation and, often, professional or legal help.

Original Medicare: how to file a redetermination

If your denial came from Original Medicare (Part A or Part B), the first appeal is a redetermination by the same Medicare Administrative Contractor that processed the claim.

Deadline. You have 120 days from the date you receive the MSN. People often mix this up with the shorter plan deadlines described below, and that confusion leads to avoidable dismissals.

How to file. Medicare offers a Redetermination Request form (CMS-20027). You can also write a letter. Whichever you choose, include:

• Your name and Medicare number, exactly as on the MSN
• The specific service or item and the date you received it
• A clear statement that you are appealing and why you disagree
• Your signature, plus your representative’s if someone is helping
• Any supporting documents, especially from your doctor

Send it to the contractor address on your MSN, and keep a complete copy. Certified mail with a return receipt is cheap insurance when a deadline matters.

What happens next. The contractor reviews your request and mails a decision. If it still says no, the decision letter explains how to ask for a reconsideration by a Qualified Independent Contractor, the second level. The CMS flowchart shows a 60-day time limit for that reconsideration decision.

Medicare Advantage and Part D: your plan decides first

When a private plan denies something, the appeal goes to that plan, not to Medicare’s claims contractors. This is the biggest procedural difference between the two paths, and it is worth understanding before you choose coverage. We cover that choice in Medicare Advantage vs. Original Medicare in 2026, and the core differences between Original Medicare and Medicare Advantage are worth a read if you are weighing options. A plain-language outside explainer on how Advantage and Medigap compare also shows why the appeal route differs by plan type.

Deadline. The first-level request is due within 65 days of the date on the denial notice. That is the notice date, not the day it reached your mailbox. If you miss it, you can ask for an extension by showing good cause, but do not plan on it.

Standard timelines. For a Medicare Advantage plan, a standard pre-service appeal can take up to 30 days, and an appeal about a payment can take up to 60 days, according to CMS guidance on Medicare Advantage appeals.

Automatic escalation. If your Advantage plan upholds its denial on reconsideration, it must forward the case to the Independent Review Entity. You do not have to file a separate second-level request in that situation.

Part D drugs. A denied prescription follows the Part D path: coverage determination, then redetermination by the plan, then independent review, and so on. Medicare lays this out on its drug plan appeals page, and the Part D flow chart shows the 65 days to file and the 72-hour limit for expedited redeterminations. Our 48 to 72 hour checklist for Part D appeals walks through the practical steps for a denied medication.

When you cannot wait: fast appeals

A standard appeal can take weeks. If that delay could seriously jeopardize your life, your health, or your ability to regain maximum function, you can ask for an expedited decision. Plans must decide within 72 hours for items and services, and within 24 hours for Medicare Advantage Part B drugs, per CMS guidance on expedited appeals.

Two practical points:

• Ask your doctor to support the request. When a physician says the standard timeline could harm you, the plan generally must expedite.
• Hospital, skilled nursing, and home health discharges have their own track. If you believe services are ending too soon, Medicare describes a separate fast appeal process, and the deadlines there are measured in hours or a day or so, not weeks. Read the discharge notice the moment you get it.

What actually strengthens an appeal

A form that says “I disagree” rarely wins. Appeals tend to turn on evidence that fills a specific gap.

Get the appeal file first

You are entitled to a copy of the file that holds the medical and other information used to make the decision. Requesting it early shows exactly what the plan or contractor considered, so you can supply what is missing rather than repeating your disagreement. This is described in Medicare’s appeals guide.

Bring your doctor into it before you file

A formal letter of medical necessity or updated clinical notes is frequently the deciding factor at the first level. Ask the physician to address the denial reason directly: why this service, why now, and why alternatives are not suitable. Medicare’s page on Original Medicare appeals points beneficiaries toward their providers for exactly this kind of support.

Match your argument to the denial reason

Keep a paper trail

Note the date, name, and reference number of every call. Save every envelope. Write down the date you mailed the appeal. If a deadline is questioned later, these records are your proof.

Common mistakes that sink appeals

• Calling 1-800-MEDICARE and stopping there. Representatives can explain the process and guide you, but they cannot override a coverage or payment decision. The appeal has to be filed formally with the contractor or your plan, as Medicare explains in Your Medicare Rights and Protections.
• Mixing up deadlines. 120 days for Original Medicare redeterminations and 65 days for Advantage and Part D are different clocks.
• Filing with no new information. Repeating the original claim gives the reviewer no reason to change course.
• Skipping the representative form. See the next section.
• Appealing a premium to Medicare. Premium disputes tied to income go elsewhere (see below).

Helping a parent or spouse with an appeal

Many of the people who search for this topic are adult children managing a parent’s paperwork. Verbal permission on a phone call is not enough. Medicare and health plans are prohibited from discussing the details of a specific appeal with anyone other than the beneficiary unless the Appointment of Representative form (CMS-1696) or another valid written instrument is on file. Families often hit a wall for exactly this reason.

Have your relative sign the form before you call, and attach a copy to the appeal. If your relative can no longer sign for themselves, a legal document such as a power of attorney or guardianship may be needed, and an elder law attorney can tell you what applies in your state.

Premium disputes are a different appeal

If your complaint is about the amount you pay each month rather than a denied claim, the route may be different. Income-Related Monthly Adjustment Amounts (IRMAA) are decided by the Social Security Administration, not Medicare. If you receive an initial IRMAA determination notice, follow the appeal instructions on it, because Medicare representatives cannot change these assessments. If your income dropped because of retirement or another life-changing event, our IRMAA explainer covers how the Social Security form for these situations works, and our guide to Part B premiums and income limits shows how the brackets apply.

Our perspective: most denials are a gap that someone could have seen coming

We work with seniors in Fort Myers, Cape Coral, Naples and the surrounding counties, and a pattern shows up again and again. The appeal itself is rarely the hard part. The hard part is that the person finds out about a gap only when the bill or the denial arrives: an ambulance ride that was not covered the way they assumed, a medication that dropped off a formulary, a referral that needed prior authorization nobody mentioned.

Appeals are a legitimate right, and we encourage people to use them. But we would rather help you avoid being caught off guard. That means reviewing how your coverage handles the things that most often lead to denials before you need care: network rules, prior authorization, your drug list, and emergency transport. It also means being honest that an appeal is not a guaranteed fix, and that some costs are simply not covered by your plan type.

Our approach is education first and no pressure. We compare options across multiple carriers, and a consultation costs nothing and carries no obligation. If your best move is to keep the coverage you have and file a strong appeal, we will say so.

— Alston

Free help with your appeal

You do not have to do this alone, and you do not have to pay anyone to file an appeal.

• Florida’s SHINE program (Serving Health Insurance Needs of Elders) offers free, unbiased and confidential counseling through trained volunteers. The state’s program is listed by CMS with a toll-free number of (800) 963-5337, on the SHINE contact page.
• Your doctor’s office can supply records and letters, and many have staff who handle denials every day.
• XactInsure can review how your current plan handles the issue that triggered the denial, and whether a different plan, such as a Medicare Supplement or a different Medicare Advantage or emergency transport option, would leave fewer gaps. If you are in Southwest Florida, you can book a free, no-obligation consultation with us. Plan changes are only possible during certain enrollment windows, so the sooner you ask, the more options you may have.

FAQ

How do you appeal a Medicare denial?

Read the denial notice, then file within the deadline: 120 days from receiving your MSN for Original Medicare, or 65 days from the notice date for an Advantage or Part D plan. Use the Redetermination Request form (CMS-20027) or a written letter, and include your doctor’s supporting documentation. Send it to the contractor or plan named on the notice.

What is a Medicare reconsideration?

It is the second level in Original Medicare, where an independent contractor reviews your case after a redetermination goes against you. In Medicare Advantage, reconsideration is the plan’s first-level review, and if the plan upholds its denial, the case goes automatically to an Independent Review Entity.

Can I appeal Medicare premiums?

Only in certain situations. Income-based premium surcharges (IRMAA) are decided and appealed through the Social Security Administration, not Medicare, and the notice you receive explains how. Medicare representatives cannot change those assessments.

What are the levels of appeal for Medicare?

There are five: a first decision by the contractor or your plan, an independent review, an ALJ hearing, the Medicare Appeals Council, and federal court. In 2026 the ALJ level requires at least $200 in dispute and federal court requires at least $1,960.

Can I file an appeal after the deadline?

Sometimes. You can request an extension by showing good cause, such as a serious illness or not receiving the notice, but approval is not guaranteed. File on time whenever you can.

Sources

• Appeals in Original Medicare, Medicare.gov
• Medicare Appeals publication, Medicare.gov
• CMS Medicare Initial Determination Appeals Process flowchart
• Appeals in a Medicare drug plan, Medicare.gov
• CMS Medicare Part D appeals flow chart
• Fast appeals, Medicare.gov
• Appeals forms, Medicare.gov
• Your Medicare Rights and Protections, Medicare.gov
• Initial IRMAA notice, Medicare.gov
• CMS home page, Medicare Advantage appeal timeframes
• SHINE, CMS contact listing

Recommended

• 48–72 Hour Checklist for U.S. Part D Appeals
• Medicare Secondary Payer Rules: U.S. Caregivers May Owe After Claims