← All guides

How to appeal a Medicare denial

A denied claim shows up on your Medicare Summary Notice, the statement Original Medicare mails at least twice a year. That notice is not a bill, and a denial does not always mean you owe the money. This page walks through the two questions in the order people ask them: do I have to pay, and how do I appeal.

This page is about a claim that Medicare has already processed and denied, such as a blood test. If a hospital or nursing facility is telling you that your care is ending too soon, that is a different and much faster process; see how to appeal a hospital discharge.

First: do I have to pay?

Medicare.gov describes the Medicare Summary Notice this way: "It's not a bill. It's a notice that people with Original Medicare get in the mail at least twice a year for their Medicare Part A and Part B-covered services." Every page of the notice carries the words "THIS IS NOT A BILL." A bill, if there is one, comes from the provider.

The column to read is "Maximum You May Be Billed." The notice defines it: "This is the total amount the provider is allowed to bill you, and can include a deductible, coinsurance, and other charges not covered. If you have Medicare Supplement Insurance (Medigap policy) or other insurance, it may pay all or part of this amount."

Whether a denied service lands in that column depends on a rule called limitation on liability. Medicare's Claims Processing Manual says the rule applies "only to claims for items and/or services submitted by healthcare providers or suppliers that have taken assignment," and only to certain kinds of denial, including services "found to be not reasonable and necessary for the diagnosis or treatment of illness or injury." That is the denial this page is about. The manual then sorts the outcome by who knew, or should have known, that Medicare would not pay:

• "If the beneficiary knew, or should have known (e.g. a valid liability notice such as an ABN, Form CMS-R-131 was issued and the beneficiary consented to receiving the item or service)," liability "Rests with the beneficiary," and "The beneficiary is responsible for making payment for the usual and customary charges to the healthcare provider or supplier for the denied item and/or service."
• "If the beneficiary did not know (and should not have known), and the healthcare provider or supplier knew, or should have known," liability "Rests with the healthcare provider or supplier," and "The beneficiary may not be charged for any costs related to the denied item and/or service, including copayments and deductibles."
• "If neither the beneficiary nor the healthcare provider or supplier knew, and could not reasonably be expected to have known," then "The Medicare program makes the payment for the assigned claim."

The manual adds: "If both the beneficiary and the healthcare provider or supplier are found to have knowledge, the beneficiary will be held liable." And it gives you a way to contest the liability finding itself: the beneficiary "has the right to appeal both the issue of coverage for the claim and determination of liability."

What an ABN is, and what signing it means

The written warning is the Advance Beneficiary Notice of Noncoverage, form CMS-R-131. The Medicare & You handbook explains it: "your doctor, other health care provider, or supplier may give you a written notice if they think Medicare won't pay for the items or services you'll get. ... If you choose to get the items or services listed on the notice, you're agreeing to pay if Medicare doesn't." The form itself opens: "Medicare doesn't pay for everything, even some care you or your health care provider think you need. We expect Medicare may not pay for the item, test, service or care listed below. If Medicare doesn't pay, you may have to pay."

The form has three checkboxes. Option 1 reads: "I want the item, test, service or care listed above, and I want Medicare to be billed for an official decision on payment, which I'll get on a Medicare Summary Notice (MSN). You can ask to be paid now. I understand that if Medicare doesn't pay, I'm responsible to pay, but I can appeal to Medicare by following the directions on the MSN. If Medicare does pay, you'll refund any payments I made to you, minus co-pays or deductibles." Option 2 is the same test without billing Medicare, and "I understand that I can't appeal, since Medicare isn't billed." Option 3 is declining the test.

So if you signed Option 1 and the claim was denied, the provider may bill you, and the manual says "The charge may be the healthcare provider or supplier's usual and customary fee for that item or service and is not limited to the Medicare fee schedule." The handbook adds one more thing worth knowing: "An ABN isn't an official denial of coverage by Medicare. If Medicare denies payment, you can still file an appeal once you get the 'Medicare Summary Notice' (MSN) showing the item or service in question."

If you were never given an ABN when one was required, the rule cuts the other way. The manual: "If the beneficiary does not receive proper notice when required, s/he is relieved from liability." CMS tells providers the same in its notices booklet: "We may hold you financially liable and you can't collect payment from the patient if you don't issue the required notice or your MAC finds the notice invalid." And the handbook, for the patient who already paid: "If your provider was required to give you this notice but didn't, in most cases, your provider must give you a refund for what you paid for the item or service." The ABN instructions also say the notice must be delivered "before providing the items or services" and that "ABNs are never required in emergency situations."

One line on the claim codes, in case you see them on a bill or remittance: modifier GA means the provider issued a required ABN and has it on file, and modifier GZ means the provider expected a medical-necessity denial and "didn't issue an ABN."

Two cautions. First, all of this is the Original Medicare rule; CMS tells providers, "Don't use an advance written notice of non-coverage for items and services you provide under Medicare Part C or Part D." Second, if the doctor did not take assignment on the claim, a separate refund rule applies: a physician who does not accept assignment "must refund any amounts collected from the beneficiary for services otherwise covered if Medicare payment is denied because the services are found to be not reasonable and necessary," unless the physician "did not know, and could not reasonably have been expected to know" or gave you written notice before the service and you "signed a statement agreeing to pay for that service."

Reading the notice: the reason and the deadline

On the claim pages, the "Service Approved?" column "tells you if Medicare covered this service." A denied line shows "NO" and a letter that points to a note underneath. On CMS's sample Part B notice, the medical-necessity note reads: "This service was denied. The information provided does not support the need for this service or item." That sentence is the whole explanation the notice gives. It does not say which rule, or which piece of information was missing. To find out, the notice says: "Call 1-800-MEDICARE (1-800-633-4227) for more information about a coverage or payment decision on this notice, including laws or policies used to make the decision."

The notice also tells you to check with the provider before anything else: "If a claim was denied, call or write the provider and ask for an itemized statement for any claim. Make sure they sent in the right information. If they didn't, ask the provider to contact our claims office to correct the error." Medicare.gov says the same: "If an item or service is denied, call your doctor's or other health care provider's office to make sure they submitted the correct information. If not, the office may resubmit." A corrected claim and an appeal are two different things, and CMS notes that "MACs do not process claim corrections involving minor errors and omissions through the appeals process."

The deadline is on the last page, under the heading "How to Handle Denied Claims or File an Appeal." The wording: "Appeals must be filed in writing. Use the form to the right. Our claims office must receive your appeal within 120 days from the date you get this notice. We must receive your appeal by:" followed by a printed date. Medicare.gov's explainer for the notice says the same thing more plainly: "You have 120 days to appeal your claims. The date listed in the box is when your appeal must be received by us." Note the word "receive." The regulation says "The request is considered as filed on the date it is received by the contractor," and it presumes you got the notice "5 calendar days after the date of the notice of initial determination, unless there is evidence to the contrary."

If you miss the date: "you may still file an appeal and get a decision if you can show good cause for missing the deadline (for example, if you have a disability, illness, or accident that delayed you from sending it by the deadline)." The regulation's examples of good cause include that "The party was prevented by serious illness from contacting the contractor," "The party had a death or serious illness in his or her immediate family," and "The party did not receive notice of the determination or decision."

Level 1: the redetermination

Medicare.gov: "The first level of appeal in Original Medicare is called a Redetermination." CMS describes it as "a review of the claim by Medicare Administrative Contractor (MAC) personnel not involved in the initial claim determination." There is no minimum dollar amount: "A minimum monetary threshold on the claim is not required to request a redetermination."

The deadline. 120 days, as above.

The form or a letter. CMS: "A redetermination must be requested in writing. There are 2 ways that a party can request a redetermination: Fill out the form CMS-20027 ... Make a written request containing all of the following information: Beneficiary name; Medicare number; Specific service(s) and/or item(s) for which a redetermination is being requested; Specific date(s) of service; Name of the party, or the representative of the party; An explanation of why the appellant disagrees with the contractor's determination." The form's own fields ask for the same things, plus "Date of the initial determination notice (mm/dd/yyyy) (please include a copy of the notice with this request)" and a line that begins "I do not agree with the determination decision on my claim because:". The form is at cms.gov (CMS-20027), or, per the Medicare Appeals booklet, "call 1-800-MEDICARE (1-800-633-4227)" to get a copy.

You can also do it on the notice itself. The notice's own steps: "1 Circle the service(s) or claim(s) you disagree with on this notice. 2 Explain in writing why you disagree with the decision. Include your explanation on this notice or, if you need more space, attach a separate page to this notice. 3 Fill in all of the following: Your or your representative's full name (print) Your telephone number Your complete Medicare number 4 Include any other information you have about your appeal. You can ask your provider for any information that will help you. 5 Write your Medicare number on all documents that you send. 6 Make copies of this notice and all supporting documents for your records. 7 Mail this notice and all supporting documents to the following address:" and then the claims office address.

Where to send it. To the contractor that denied the claim, at the address printed on the notice. CMS: "The redetermination request must be sent to the MAC that made the initial claim determination (this information is on the MSN and the RA). Check the MAC website for more information on how to file appeals. Most MACs allow electronic submission of appeals through their website." Medicare.gov: "Mail your documentation to the Medicare Claims office address listed in Step 7 on the last page of your MSN."

What to include. Medicare.gov's list ends with "Any other information that may help your case (like a doctor's note)." The form asks you to check "I have evidence to submit" or "I do not have evidence to submit," and says: "You may also submit additional evidence at a later time, but all evidence must be received prior to the issuance of the redetermination." The Medicare Appeals booklet adds, "Keep a copy of everything you send to Medicare as part of your appeal."

The decision. Medicare.gov: "You'll generally get a decision from the Medicare Administrative Contractor (MAC) within 60 days after they get your appeal. If the MAC decides that Medicare will cover the appealed item(s) or service(s), it will be listed on your next MSN. If the MAC decides that Medicare won't cover the appealed item(s) or service(s), you'll get a written decision letter (called a 'Medicare Redetermination Notice')." The booklet notes one wrinkle: "The MAC will get an extra 14 calendar days to make a decision each time you send them more information or evidence."

Someone can help you. Medicare.gov: "If you have a trusted family member or friend helping you with a complaint, you can appoint them as a representative." The form is the Appointment of Representative, CMS-1696, and a copy goes in with the appeal.

Levels 2 through 5

Medicare.gov: "There are 5 levels of appeal. If you disagree with the decision made at any level of the process, you can usually go to the next level. At each level you'll get a decision letter with instructions on how to move to the next level." The days below are calendar days, and for each one Medicare presumes you got the previous decision five days after its date.

A few details from the CMS pages for each level. At Level 2, use form CMS-20033 or a letter, send it to "the QIC listed on your Medicare Redetermination Notice," and send everything you have: "Any documentation not submitted at the reconsideration level may be excluded from consideration at subsequent levels of appeal unless good cause is shown for not submitting the documentation previously." At Level 3, "An ALJ hearing is usually held by phone or video-teleconference," the request goes on form OMHA-100, and you "may be able to combine claims" to reach the dollar minimum. The amount that counts is what is still in dispute: "the actual amount charged the individual for the items and services in the disputed claim, reduced by: Any Medicare payments already made or awarded for the items or services; and Any deductible and/or coinsurance amounts that may be collected for the items or services." At Level 4 the form is DAB-101. At Level 5 the case is filed "in the district court of the United States for the judicial district in which the party resides."

The two dollar figures change every January. The Federal Register notice for 2026 says: "The calendar year 2026 AIC threshold amounts are $200 for ALJ hearings and $1,960 for judicial review," effective for requests "filed on or after January 1, 2026." The 2027 figures are already published: "The calendar year 2027 AIC threshold amounts are $200 for ALJ hearings and $2,000 for judicial review," effective January 1, 2027. The same thresholds "also apply to Medicare Part D appeals."

If you have Medicare Advantage

The first two levels are different. Medicare.gov: "Coverage decisions in a Medicare Advantage Plan are called 'Organization Determinations,'" and "Level 1 appeals in a Medicare Advantage Plan are called 'Health Plan Reconsiderations.'" The deadline on medicare.gov: "You, your representative, or your doctor or healthcare provider must file an appeal within 65 days from the date on the initial denial notice sent by your plan. If you miss the deadline, you must give a reason for filing late."

If you have seen "60 days" elsewhere, both are describing the same rule. The regulation says "a request for reconsideration must be filed within 60 calendar days after receipt of the written organization determination notice," and "The date of receipt of the organization determination is presumed to be 5 calendar days after the date of the written organization determination." Sixty days after a receipt date five days out is 65 days from the date on the notice, which is how medicare.gov and the CMS pages now put it.

The plan's time to answer, from medicare.gov: "Pre-service appeal: 30 days; Payment appeal: 60 days; Part B drugs appeal: 7 days; Fast appeal: 72 hours." A lab test you already had is a payment appeal. Then: "If the plan decides against you (fully or partially), your appeal is automatically sent to level 2," which is "Review by an Independent Review Entity." As of this year the entity changed. CMS: "Effective May 1, 2026, C2C Innovative Solutions, Inc. (C2C) is the Part C IRE. The former Part C IRE, MAXIMUS, will continue to process appeal requests received on or before April 30, 2026." From there the path rejoins the table above: "You have 60 days from the date of the IRE's decision to ask for a level 3 appeal," with the same $200 and $1,960 minimums for 2026.

One line on drug plans: "Level 1 appeals in a Medicare drug plan are called redeterminations," the deadline is also "65 days from the date on the initial denial notice sent by your plan," and the Level 2 reviewer is the same company, since "C2C Innovative Solutions, Inc. is the current Part D IRE."

Complaint or appeal?

Medicare.gov draws the line this way: "File a complaint if: You have a problem with the quality of the care you got or are getting; You have a problem with how you're being treated by your plans. File an appeal if: You have an issue with a plans' refusal to cover a service, supply, or prescription. You got a bill for a claim you already submitted." A complaint is "also called a 'grievance.'" A denied lab test is an appeal.

Who to call

Medicare: "1-800-MEDICARE (1-800-633-4227). TTY users can call 1-877-486-2048." Medicare.gov describes the line as "a real person, 24 hours a day, 7 days week (except some federal holidays)." For free one-on-one help, medicare.gov points to the State Health Insurance Assistance Program: "Visit shiphelp.org to get the phone number for your local SHIP and get free, personalized health insurance counseling." The notice itself says: "Call 1-800-MEDICARE or your State Health Insurance Program (see page 2) for help before you file your written appeal, including help appointing a representative."

If the denied claim is a lab test

For blood work and other lab tests, the denial note on the notice ("The information provided does not support the need for this service or item") points at what was on the claim, and the piece of information CMS says every claim must carry is the diagnosis: "Every service you bill must indicate the specific sign, symptom, or patient complaint that makes the service reasonable and necessary." So the first thing to check is the diagnosis. For the common tests covered by a national rule, that rule is paired with a list of diagnosis codes, and CMS's ABN instructions list, as the "commonly used reasons for non-coverage," these two first: "Medicare does not pay for this test for your condition." and "Medicare does not pay for this test as often as this (denied as too frequent)."

That is what ClaraCover's lookup pages show. Our blood work coverage page explains which diagnoses satisfy each rule, and Before you go walks through what to ask before the draw. If you are reading this after a denial, use them the other way around: find the test, see what the rule wanted, and compare it to the diagnosis on your doctor's order. Ask the office which diagnosis code went on the claim.

Then there are two possible paths, and the office should tell you which one fits. If the claim simply went in with the wrong or an incomplete diagnosis, the notice says to ask the provider to "contact our claims office to correct the error," and the office "may resubmit." If the claim was accurate but your records support a diagnosis that the rule covers, your redetermination request can ask the doctor for a note that says so, and that note goes in with the form. We say this plainly because it is the fix people look for first, and just as plainly: it is not a promise. The doctor has to agree the diagnosis is real and documented, and the contractor decides the appeal. No one on this site can tell you how it will come out. For what "reasonable and necessary" means and how the diagnosis lists work, see what Medicare means by "reasonable and necessary".

If you are handling this for a parent and would rather have a person go through every claim with you, that is a paid service we offer: the claims review for families.

Before you send it

This is ClaraCover's checklist, built from the rules above.

1. Find two dates. The date on the notice, and the "We must receive your appeal by" date on the last page. Medicare has to receive it by then, not just see a postmark.
2. Pick the form or the letter. Form CMS-20027, or a letter with your name, Medicare number, the service, the date of service, and why you disagree. Circling the line on a copy of the notice and writing on it also counts.
3. Get the doctor's note. Ask the ordering office for a note or the record that shows the reason for the test, and which diagnosis was on the order. Include it.
4. Send copies, keep originals. The notice says to "Make copies of this notice and all supporting documents for your records," and to "Write your Medicare number on all documents that you send."
5. Send it where the notice says. The "Medicare Claims Office" address in step 7 on the last page, or the contractor's website if it takes appeals online.

Sources

• Medicare.gov: Appeals (overview)
• Medicare.gov: Appeals in Original Medicare
• Medicare.gov: Medicare Summary Notice
• Medicare.gov: What's in your Medicare Summary Notice? (Part B sample explainer)
• CMS: Sample Part B Medicare Summary Notice
• CMS: First Level of Appeal, Redetermination by a Medicare Contractor
• CMS: Second Level of Appeal, Reconsideration by a Qualified Independent Contractor
• CMS: Third Level of Appeal, Decision by Office of Medicare Hearings and Appeals
• CMS: Fourth Level of Appeal, Review by the Medicare Appeals Council
• CMS: Fifth Level of Appeal, Judicial Review in Federal District Court
• CMS: Form CMS-20027, Medicare Redetermination Request Form
• CMS: Form CMS-20033, Medicare Reconsideration Request Form
• CMS: Form CMS-1696, Appointment of Representative
• CMS: MLN006562, Medicare Parts A & B Appeals Process (September 2025)
• Medicare.gov: Medicare Appeals (booklet 11525, April 2026)
• Medicare.gov: Medicare & You 2027, section 8
• eCFR: 42 CFR 405.942, time frame for filing a request for a redetermination
• eCFR: 42 CFR 405.1006, amount in controversy
• Federal Register: Amount in controversy threshold amounts for calendar year 2026 (December 4, 2025)
• Federal Register: Amount in controversy threshold amounts for calendar year 2027 (September 16, 2026)
• CMS: Medicare Claims Processing Manual, chapter 30, Financial Liability Protections
• CMS: Advance Beneficiary Notice of Noncoverage (form CMS-R-131)
• CMS: ABN Form Instructions
• CMS: MLN006266, Medicare Advance Written Notices of Non-coverage (May 2025)
• eCFR: 42 CFR 411.408, refunds for physician services not accepted on assignment
• Medicare.gov: Appeals in a Medicare health plan
• CMS: Parts C & D appeals and grievances (managed care)
• CMS: Review by the Part C Independent Review Entity
• eCFR: 42 CFR 422.582, request for a standard reconsideration
• Medicare.gov: Appeals in a Medicare drug plan
• CMS: Part D reconsiderations by the Independent Review Entity
• Medicare.gov: Complaints (grievances)

Checked September 27, 2026. This page explains published Medicare rules. It is not medical, legal, or insurance advice, cannot tell you whether you owe a particular bill or how your appeal will be decided, and does not replace the instructions printed on your own Medicare Summary Notice; Medicare, your State Health Insurance Assistance Program, and your doctor's office can help with your own case. ClaraCover has no relationship with any provider, plan, or contractor.