You opened a letter and it said Medicare denied your claim. Or your doctor called and said the plan will not cover the surgery. Deep breath. This happens all the time. Medicare has a five-level appeal system, and about 4 out of 10 first-level appeals succeed. Most people never file one. Here is how the process actually works, in plain language.
The short answer
Medicare has 5 levels of appeal. Most cases end at Level 1 or 2. You do not need a lawyer. You do not pay a fee. The deadlines are strict, so start fast. Original Medicare gives you 120 days for Level 1. Medicare Advantage and Part D give you 60 days.
Your best chance to win is Level 1 and Level 2. About 40% of denials get reversed at Level 1. Another chunk get reversed at Level 2. If you have real medical support from your doctor, your odds are even better.
Why Medicare denies claims
Denials usually fall into one of these buckets:
- Not medically necessary. The most common reason. Medicare's computer says the service is not needed based on your diagnosis codes.
- Not covered by Medicare. Some services are excluded (routine dental, cosmetic, certain custodial care).
- Wrong billing code. The doctor's office used a code Medicare does not pay for. Often fixable.
- Missing information. The claim is missing paperwork Medicare wants.
- Duplicate claim. Medicare thinks it already paid this one.
- Prior authorization not obtained. Common in Medicare Advantage.
The denial letter tells you which one. Read it carefully. The reason code helps you build your appeal.
The Original Medicare 5 levels of appeal
Level 1: Redetermination (MAC)
- Who reviews: Your Medicare Administrative Contractor (MAC), the private company that handles Medicare claims in your region
- Deadline to file: 120 days from the date on your Medicare Summary Notice
- Decision time: 60 days from receipt
- Cost: Free
- How to file: Fill out form CMS-20027 or write a letter with your Medicare number, service dates, and reason for the appeal
Level 2: Reconsideration (QIC)
- Who reviews: A Qualified Independent Contractor (QIC), a different company than the MAC
- Deadline to file: 180 days after Level 1 decision
- Decision time: 60 days
- Cost: Free
- How to file: Form CMS-20033 or a written statement
Level 3: ALJ hearing
- Who reviews: Administrative Law Judge at the Office of Medicare Hearings and Appeals
- Deadline to file: 60 days after Level 2 decision
- Decision time: Usually within 90 days, but backlogs push some cases to a year or longer
- Cost: Free to file, but must meet a minimum dollar threshold (check current CMS rates, usually around $190 in dispute)
- How it works: A hearing by phone or video where you present your case
Level 4: Medicare Appeals Council
- Who reviews: A panel at the Departmental Appeals Board
- Deadline to file: 60 days after Level 3 decision
- Decision time: 90 days
- Cost: Free
Level 5: Federal district court
- Who reviews: A federal judge
- Deadline to file: 60 days after Level 4 decision
- Cost: Court filing fees apply, and a much higher minimum dollar amount in dispute (usually well above $1,900, check current CMS rates)
- How it works: A lawsuit against the Secretary of Health and Human Services. Almost always requires an attorney
Step by step: filing your first appeal
Step 1: Read the Medicare Summary Notice (MSN)
Your MSN arrives every 3 months by mail if you had Part A or B claims. Or you can log into MyMedicare.gov to see it faster. The last column, "Maximum you may be billed," shows what you owe. If a service was denied, you will see the reason code and a plain-English explanation.
Step 2: Circle every claim you want to appeal
Circle the specific service line. Note the date, the provider, and the amount denied. Each service line is its own appeal.
Step 3: Gather your evidence
Ask your doctor for:
- A letter of medical necessity explaining why the service was needed
- Copies of relevant medical records (tests, exam notes, imaging)
- The specific diagnosis code (ICD-10) that supports the service
Most doctor's offices will do this for you if you ask. It costs them nothing and helps them get paid.
Step 4: Fill out the redetermination form or write a letter
Form CMS-20027 is at Medicare.gov. If you prefer a letter, include: your name, Medicare number, service date, provider name, service being appealed, and why you think the denial was wrong.
Attach your doctor's letter and any records.
Step 5: Mail everything to the MAC address on your MSN
The address is printed on the MSN, near the appeal instructions. Send it certified mail so you have proof of delivery. Keep copies of everything.
Step 6: Wait for the decision
The MAC has 60 days to decide. You will get a letter called a Medicare Redetermination Notice (MRN) with the outcome. If you win, Medicare pays the claim. If you lose, the letter explains how to move to Level 2.
Fast appeals for urgent care
If waiting could seriously hurt your health, you can request an expedited (fast) appeal. This applies to:
- Denials of ongoing hospital, skilled nursing, or home health care that Medicare says should end
- Any Medicare Advantage denial for services you have not yet received
- Part D denials for a drug you need urgently
Fast appeals get answered in 72 hours instead of 60 days. Ask for one whenever the timing matters.
Medicare Advantage and Part D appeals are different
Medicare Advantage plans and Part D drug plans use a similar 5-level structure but with different names and deadlines.
| Original Medicare | Medicare Advantage / Part D |
|---|---|
| Level 1: MAC Redetermination | Level 1: Plan Reconsideration (by the plan itself) |
| Level 2: QIC Reconsideration | Level 2: Independent Review Entity (IRE) |
| Level 3: ALJ Hearing | Level 3: ALJ Hearing |
| Level 4: Appeals Council | Level 4: Appeals Council |
| Level 5: Federal Court | Level 5: Federal Court |
For Advantage and Part D, your deadline for Level 1 is 60 days from the denial, not 120. The plan sends you a form or you can call.
See our related article on Medicare prior authorization, since most Advantage denials start there.
What helps you win
A strong letter of medical necessity
Your doctor's letter is the single most important document. It should explicitly say:
- Your diagnosis with ICD-10 codes
- Why the specific service was medically necessary for that diagnosis
- Why alternative treatments would not work or were tried and failed
- Citations to Medicare's own coverage guidelines when possible
Medical records that back it up
Include exam notes, imaging reports, lab results, and any second opinions. Do not just send a form. Send proof.
Persistence
Many people win on Level 2 after losing Level 1. The QIC is independent and often reverses MAC denials. Do not stop at Level 1 if you have a real case.
Free help
Your State Health Insurance Assistance Program (SHIP) offers free personal help with appeals. Every state has one. Find yours at Medicare.gov's help finder.
Real example: home health denial
James, 74, needed home health nursing after knee replacement. Medicare initially denied 2 weeks of the care as "not medically necessary."
His daughter helped him file a Level 1 appeal. His surgeon wrote a 1 page letter explaining he had a wound infection and could not travel safely. She attached the surgeon's notes and the discharge orders.
Result: Medicare reversed the denial 42 days later. Paid the full claim, about $2,300.
Time invested: about 3 hours. Cost: certified mail postage.
Common mistakes
Missing the deadline
The number one reason appeals fail. Original Medicare: 120 days. Advantage and Part D: 60 days. Mark your calendar the day you get the denial.
Writing "I disagree" and nothing else
A one-line appeal loses. You have to explain why the denial is wrong and provide medical evidence.
Not involving your doctor
Your doctor's letter of medical necessity is your strongest tool. Ask for it. Most offices will help without complaint.
Giving up after Level 1
Level 2 is an independent review by a different contractor. Many Level 1 losses become Level 2 wins.
Paying the bill before you appeal
You can appeal a claim you have not paid yet. In fact, do not pay disputed bills while an appeal is pending. Ask the provider to hold off.
The bottom line
Medicare denies claims for lots of reasons, and some of those denials are wrong. You have a real appeal process. Level 1 is a form and a doctor's letter. Level 2 is the same, sent to a different reviewer. Together they resolve most cases in your favor if the service was truly medically needed.
Do not let a denial letter scare you into paying a bill you should not owe. And do not miss the deadline. If you need help walking through your options, book a free 20 minute call and I will help you sort what to do first.
Related reading: Medicare observation status vs admission (a common source of surprise denials) and the top 10 hidden costs of Medicare.
Frequently asked questions
How long do I have to appeal a Medicare denial?
Original Medicare: 120 days from the MSN date. Medicare Advantage and Part D: 60 days from the denial notice. Deadlines are strict.
What is a Medicare redetermination?
The Level 1 appeal for Original Medicare. Reviewed by your MAC. Free. Decision usually in 60 days. About 40% succeed.
How many levels of Medicare appeal are there?
Five: Redetermination, Reconsideration, ALJ hearing, Appeals Council, and federal district court. You must lose each level before moving up.
Do I need a lawyer to appeal a Medicare denial?
Not for Levels 1 or 2. Some people use one at Level 3 or above. Your SHIP counselor helps free at every level.
Can I get a fast appeal for urgent Medicare denials?
Yes. Expedited appeals get answered in 72 hours if waiting would harm your health. Ask for one when timing matters.