Medicare Denied It? How to Read the Letter and Appeal, in Plain English

A Medicare letter sitting on the kitchen table can ruin a week. The type is small, the codes mean nothing, and the one question that matters, "do I owe this, and can they really refuse to pay?", is answered nowhere on the page. Here is that answer, in order.

First: which letter are you holding?

• Medicare Summary Notice (MSN): arrives quarterly if you have Original Medicare and had claims. It lists what providers billed, what Medicare paid, and what you may owe. It says "This is not a bill" across the top, and it means it. This is also where you learn a claim was denied.
• Explanation of Benefits (EOB): the monthly equivalent from a Medicare Advantage or Part D drug plan. Also not a bill. Our EOB guide covers the numbers in detail.
• A denial or "Notice of Denial" letter: a decision from your plan refusing to cover or pre-approve something. This one has a deadline attached and is built to be appealed.
• An actual bill: comes from the provider, never from Medicare. Before paying it, match it against the MSN or EOB for that date of service.

Reading the MSN without the headache

Each claim line shows the service, whether Medicare approved it, and a "maximum you may be billed" figure. Two spots matter most: the claim lines marked unapproved or denied, and the final page, which explains why and lays out your appeal rights with the exact deadline and address. The denial reasons are often mundane: a billing code the provider got wrong, a missing diagnosis, paperwork that never arrived. Those get fixed by the provider's billing office resubmitting, and a call asking them to do so is often the entire fight.

Your appeal rights and the deadlines that matter

• Original Medicare: you have 120 days from receiving the MSN. Circle the denied item on the MSN, sign it, attach anything from your doctor that supports it, keep a copy, and mail it to the address on the notice. That's a valid appeal, called a redetermination. Details at medicare.gov/claims-appeals.
• Medicare Advantage: you have 60 days from the denial notice to ask the plan to reconsider. If the plan still says no, your case is automatically sent to an independent reviewer outside the plan. (Chronic MA prior-auth friction is also a plan-choice signal; the Medigap comparison covers when and how switching is possible.)
• Part D (drugs): you have 60 days, and your prescriber can request a coverage exception with a supporting statement, which is often the fastest route.
• Need it fast? If waiting would seriously harm your health, say the word "expedited" and have your doctor back it up. Fast-track appeals get decided in days, sometimes 72 hours. (Hospital discharges and ending nursing or home-health care have their own even faster process with midnight and noon deadlines; the fast-appeal guide covers it.)

Why appealing is worth your time

KFF's analysis of Medicare Advantage found that when denials are appealed, more than 8 in 10 are overturned in whole or in part. And yet only about 1 in 10 denials are appealed at all. Most people take the first no as the final answer. The insurers' own numbers say the first no is frequently wrong, and the system corrects it for the people who ask.

Free help that answers to you, and no one else

• SHIP (State Health Insurance Assistance Program): free, unbiased, one-on-one counseling from a trained person in your state. They sell nothing. Find yours at shiphelp.org or call 877-839-2675.
• 1-800-MEDICARE (1-800-633-4227): open around the clock; they can explain any notice and check a claim's status.
• Medicare Rights Center helpline: 800-333-4114, a national nonprofit that walks people through denials and appeals.

One more thing: the phone calls

Medicare does not call to sell plans, "verify" your number, or offer free equipment. Those calls are scams aimed at your Medicare number, which is worth money. Hang up without apology, and if you gave out information, call 1-800-MEDICARE. Knowing exactly what you're being charged and why, which is what the MSN gives you, is also your best scam detector: you'll spot billing for equipment or visits that never happened.