Why Was My Medicare Claim Denied And How Do I Fight It

Claims are usually denied because Medicare deems the service not medically necessary, the provider isn't enrolled, or a coding error occurred. You fight it by following the 5-stage appeals process on your Medicare Summary Notice, starting with a written redetermination request within 120 days.

The real reason your medicare claim was denied

Your Medicare Summary Notice (MSN) uses a three-digit code next to each denied item. That code tells you exactly why the claim failed. The most common trigger is a “lack of medical necessity” (code 1.2). This means Medicare’s automated review decided the service didn’t match your diagnosis or treatment history. For example, an MRI for lower back pain without a documented failed trial of physical therapy is a classic denial. The second most common reason is a billing or coding mismatch (code 1.3). Your provider used the wrong Current Procedural Terminology (CPT) code, say, a new patient visit code when you’ve been seen in that clinic for three years. Frequency limits (code 1.4) hit when you exceed Medicare’s allowed number of a particular procedure, like more than one colonoscopy per 24 months for average-risk patients. Finally, “non-covered services” (code 1.1) means the item is statutorily excluded, such as routine dental extractions, hearing aids, or most over-the-counter supplements. The MSN also lists a “remark code” in plain English, so read that line before calling anyone.

Claims are usually denied because Medicare deems the care not medically necessary, the provider isn’t enrolled, or a coding error occurred. You fight it by following the 5-stage appeals process on your Medicare Summary Notice. Start with a written redetermination request within 120 days. Do not panic. A denial is not a bill. Most denials are overturned at the first stage if you act quickly and submit the right paperwork from your doctor.

When you actually can't fight it

There is one situation where an appeal is a waste of your time: if you signed an Advance Beneficiary Notice (ABN) before the procedure and the denial reason is “statutorily excluded.” An ABN is a form your provider gives you when they believe Medicare won’t pay. Signing it means you agree to pay out-of-pocket if Medicare denies the claim. If the procedure is excluded by law, like a chiropractic adjustment beyond the 12-visit limit or a screening test not on the approved list, no appeal will change that because the statute forbids coverage. You also lose your right to appeal if you miss the firm 120-day deadline from the date on the MSN. The clock does not pause for holidays. Medicare will not accept a late redetermination for any reason. Finally, if the denial is for care you already received and you did not get a written order from your doctor before the date of care, you have no evidence to overturn a “not medically necessary” decision.

How to write a redetermination that wins

Your first appeal is a “redetermination,” and it must be in writing. Do not use the phone. Write “REDETERMINATION REQUEST” at the top of a plain sheet of paper. Include your full name, Medicare number, the date of care, and the exact procedure code from the MSN. Then, attach two things: a letter from your treating physician explaining why the care was medically necessary, and any test results or clinical notes that support that explanation. The exact language to use is direct: “Based on my physician’s clinical judgment and the attached records, this procedure is medically necessary to diagnose or treat my condition, and the denial reason (cite the code) is incorrect because [specific evidence].” Avoid vague words like “essential” or “needed.” Instead, quote your doctor’s note verbatim. For example, if the denial says “not medically necessary,” your doctor should write: “The patient’s symptoms of [symptom] have not responded to [previous treatment], and this [test/procedure] is required to rule out [diagnosis].” Send it via certified mail with a return receipt. Keep a copy of everything. You have 120 days from the MSN date, but the faster you send it, the faster you get a decision, typically within 60 days.

What happens if they say no again

If your redetermination is denied, you automatically move to stage 2: a reconsideration by a Qualified Independent Contractor (QIC). This is a third-party review that does not work for Medicare. You must request this within 180 days of the redetermination decision. The QIC will look only at the evidence you submitted in stage 1, so do not add new facts here. Just resubmit the same packet. If the QIC denies you, the stakes change. For claims under the amount the Centers for Medicare & Medicaid Services (CMS) currently sets as the minimum for an Administrative Law Judge hearing, check your MSN and the official CMS.gov website for the exact threshold, you cannot go further. For claims between that lower threshold and the higher amount CMS sets for a full hearing right, you can request an Administrative Law Judge (ALJ) hearing, but only if the amount in dispute meets the threshold. For amounts over the higher threshold CMS establishes, you have the right to an ALJ hearing. This is a virtual or in-person session where you can present your case. Most people never get this far because they give up, but the overturn rate at the QIC stage is around 30%. At the ALJ stage it jumps to over 50% for those who persist. The key is to check the dollar amount on your MSN. If it’s below the ALJ minimum published by CMS, you’ve exhausted your appeal rights and your only option is to ask the provider to waive the charge.

This page explains how to read your Medicare Summary Notice denial codes, build a winning redetermination, and navigate every appeal stage, information you can use to compare Medicare advantage plans against original Medicare when you evaluate how each handles your right to fight a denial.

Frequently Asked Questions

What if the denial is for a procedure I already paid for out-of-pocket?

You can still appeal, but you must include a copy of the receipt and proof of payment with your redetermination request. If you win, Medicare will reimburse you directly, plus interest in some cases.

Can my doctor help me appeal, or do I have to do it alone?

Your doctor can write a supporting letter, but you must file the appeal yourself. No one else can sign the redetermination form on your behalf, though a family member can mail it if you give written authorization.

What if I miss the 120-day deadline because I was in the hospital?

Medicare will not extend the deadline for illness, but you can request a “good cause” extension if you were incapacitated and can provide a doctor’s note. This is rare, so call the number on your MSN immediately to ask.

Does a denial affect my ability to enroll in Medicare without a penalty?

No, an appeal denial does not affect your enrollment status or your future coverage. It only applies to that specific claim, and you can still use your benefits normally after the decision. Your ability to enroll in Medicare without a penalty is governed by your Initial Enrollment Period or a Special Enrollment Period, not by individual claim decisions.

Is there a difference between a denial and a “non-covered” notice?

Yes. A denial means Medicare reviewed the claim and said no. A “non-covered” notice (like a Medicare Summary Notice code 1.1) means the procedure is never covered, regardless of medical necessity. For the latter, your appeal would need to prove the procedure actually falls under a covered category, which is rare.

How does this affect my Medicare cost in 2025?

A denied claim does not change your premium, but if you lose an appeal on a non-covered procedure, you are responsible for the full provider charge. Understanding the appeals process helps you manage your overall healthcare & medicare budget, because your Medicare cost in 2025 will depend on which services you successfully get covered versus which you pay out-of-pocket.