Medicare Q&ASeptember 16, 2026·8 min read·By Jacob Posner, Founder & Editor
Can Medicare Deny Coverage? (2026)
Short answer: Yes. Medicare can deny coverage it finds medically unnecessary.
Full answer: Yes, Medicare can deny coverage. Original Medicare denies claims when a service is not medically necessary, experimental, or excluded under a National Coverage Determination (NCD) or Local Coverage Determination (LCD). Medicare Advantage plans deny coverage more often, mainly through prior authorization. Every denial carries appeal rights, and CMS's 2026 rule requires Medicare Advantage plans to decide standard prior authorization requests within 7 calendar days (72 hours if expedited) and state a specific reason for each denial.
Medicare denies millions of claims and prior authorization requests every year, and the rules for when it can say no differ sharply depending on whether you have Original Medicare or a Medicare Advantage plan. In 2026, a new CMS rule (CMS-0057-F) forces Medicare Advantage insurers to move faster and explain denials more clearly, but the underlying right to deny coverage has not changed.
The sections below break down exactly when Medicare can deny coverage in 2026, how denial rules differ across Original Medicare, Medicare Advantage, Medicare Part D, and Medigap, and the five-level appeal process available to fight back. For related context, see Medigap vs. Medicare Advantage and switching from Medicare Advantage back to Original Medicare.
Coverage Breakdown
Coverage by type
Plan Type
Can Deny Coverage?
Common Denial Reasons (2026)
Appeal Timeline (2026)
Original Medicare (Part A and Part B)
Yes
Not medically necessary per an NCD or LCD, custodial care, experimental treatment
120 days to file a Level 1 Redetermination; MAC decides within 60 days
Medicare Advantage (Part C)
Yes
Prior authorization denial, out-of-network care, stricter plan medical necessity criteria
7-calendar-day standard prior authorization decision (72 hours if expedited) required in 2026; internal appeal, then Independent Review Entity
Medicare Part D
Yes
Drug not on formulary, failed step therapy, exceeded quantity limit
72-hour standard coverage determination, 24-hour expedited; 7-day standard redetermination appeal
Medigap (Medicare Supplement)
No independent denial
Cannot deny an already-approved Original Medicare claim; can deny new enrollment outside the guaranteed-issue window
Claim denials appeal through Original Medicare; enrollment denials appeal through the state insurance department
Medicare coverage denials by plan type in 2026: all four plan types can restrict what they pay, but only Original Medicare and Medicare Advantage make true medical-necessity denials. CMS's 2026 prior authorization rule (CMS-0057-F) now requires Medicare Advantage plans to give a specific reason and decide standard requests within 7 calendar days (72 hours if expedited).
Yes, Medicare can deny coverage. Original Medicare denies claims when a service is not medically necessary, experimental, or excluded under a National Coverage Determination (NCD) or a Local Coverage Determination (LCD). Medicare Advantage plans deny coverage more often, mainly through prior authorization. Every denial carries appeal rights, and CMS's 2026 rule requires Medicare Advantage plans to decide standard prior authorization requests within 7 calendar days (72 hours if expedited) and state a specific reason for each denial.
How Original Medicare Denies Coverage in 2026
Original Medicare, meaning Medicare Part A and Medicare Part B combined, denies a claim when a Medicare Administrative Contractor (MAC) decides the service does not meet a National Coverage Determination (NCD) or Local Coverage Determination (LCD). NCDs are national rules set by CMS that apply everywhere; LCDs are regional rules set by each MAC and can vary by state. Common Original Medicare denials in 2026 include custodial care that does not require skilled nursing, cosmetic procedures, routine dental and vision care, and treatments CMS classifies as experimental or investigational. When a claim is denied, you receive a Medicare Summary Notice (MSN) every three months listing what was billed, what Medicare paid, and the specific reason for any denial, along with your appeal rights and deadline.
Why Medicare Advantage Plans Deny More Often
Medicare Advantage plans denied 4.1 million of the 52.8 million prior authorization requests they processed in 2024, a denial rate of about 7.7 percent, according to KFF's analysis of CMS data. Only around 11.5 percent of denied requests were formally appealed, yet 80.7 percent of the ones that were appealed got overturned, meaning the original denial was wrong. Starting January 1, 2026, the CMS Interoperability and Prior Authorization Final Rule (CMS-0057-F) requires every Medicare Advantage plan to decide standard prior authorization requests within 7 calendar days and expedited requests within 72 hours, and to give a specific clinical reason instead of a generic denial letter. Medicare Advantage plans can still apply stricter internal medical necessity criteria than Original Medicare for services without a specific NCD or LCD, which is the main reason denial rates run higher than traditional Medicare.
Does Medicare Part D Deny Prescription Drug Coverage?
Medicare Part D plans deny prescription drug coverage when a drug is not on the plan's formulary, when a cheaper alternative must be tried first under step therapy, or when a prescribed quantity exceeds the plan's limit. Every Part D denial, called a coverage determination, must be decided within 72 hours for a standard request and 24 hours for an expedited request in 2026. Your prescriber can request an exception if a formulary drug would be less effective or would cause an adverse reaction, and pharmacists must give you a written notice explaining the denial and how to appeal. Insulin remains capped at $35 per month under the Inflation Reduction Act regardless of formulary tier, and total out-of-pocket drug costs are capped at $2,100 in 2026.
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Medigap Does Not Deny Medical Claims, But It Has Limits
Medigap policies do not make medical necessity decisions, because Medigap only pays the deductibles, copayments, and coinsurance left over after Original Medicare approves a claim; if Original Medicare denies the underlying service, Medigap has nothing to pay. Medigap insurers can still deny you a policy or charge more based on health history if you apply outside your six-month Medigap Open Enrollment Period, which starts the month you turn 65 and enroll in Part B. Outside that window and outside a handful of state guaranteed-issue protections, Medigap medical underwriting works much like preexisting condition exclusions did in the individual market before the ACA banned them for ACA-compliant plans.
How to Appeal a Medicare Coverage Denial in 2026
Every Medicare denial, whether from Original Medicare, Medicare Advantage, or Part D, comes with a formal five-level appeal process, and deadlines are strict. Start by reading your denial notice (Medicare Summary Notice, Advance Beneficiary Notice, or plan denial letter) for the exact reason and the appeal deadline. Original Medicare appeals go through medicare.gov's claims and appeals process; Medicare Advantage and Part D appeals go directly through your plan first.
A copy of the denial notice (MSN, Advance Beneficiary Notice, or plan letter)
A letter from your doctor explaining why the service was medically necessary
Medical records, test results, or imaging that support the claim
The specific NCD, LCD, or plan policy number cited in the denial, if listed
Medicare appeal levels and deadlines 2026
Level
Who Decides
Deadline to File
Level 1: Redetermination
Your Medicare Administrative Contractor (MAC)
120 days from the denial notice; MAC decides within 60 days
Level 2: Reconsideration
Qualified Independent Contractor (QIC)
180 days from the redetermination notice
Level 3: ALJ Hearing
Administrative Law Judge (OMHA)
60 days from the reconsideration notice; case must involve at least $200 in 2026
Level 4: Medicare Appeals Council
Medicare Appeals Council review board
60 days from the ALJ decision
Level 5: Federal District Court
U.S. District Court
60 days from the Council decision; case must involve at least $1,960 in 2026
Medicare Advantage appeals follow a similar five-level path but start with the plan's internal reconsideration, then move to the Independent Review Entity (C2C Innovative Solutions, which replaced Maximus in 2026), then the ALJ, Council, and federal court.
Source: CMS.gov Medicare Parts A and B Appeals Process, Medicare.gov Claims and Appeals 2026
Alternatives If Your Denial Is Upheld
A denial that survives all five appeal levels is not the end of your options. Every state has a free State Health Insurance Assistance Program (SHIP) counselor who can review your denial and help you file the next appeal at no cost; find yours at shiphelp.org. If a denied service falls outside what Original Medicare, Medicare Advantage, or Part D will ever cover, such as routine dental work or cosmetic procedures, a standalone supplemental dental, vision, or hearing policy can fill the gap. Family members under 65 who lose employer coverage because of a Medicare-eligible spouse's job change can shop ACA-compliant marketplace plans, which must cover the ten essential health benefits and cannot deny enrollment or charge more for a preexisting condition.
Frequently Asked Questions
Can Original Medicare deny a claim in 2026?
Yes. Original Medicare denies a claim whenever a Medicare Administrative Contractor decides the service is not medically necessary, is experimental, or falls outside a National Coverage Determination (NCD) or Local Coverage Determination (LCD). Common denials include custodial care, cosmetic procedures, and routine dental or vision services. The denial reason appears on your Medicare Summary Notice along with the 120-day deadline to file a redetermination appeal.
Why do Medicare Advantage plans deny more claims than Original Medicare?
Medicare Advantage insurers denied about 7.7 percent of the 52.8 million prior authorization requests they processed in 2024, largely because plans can apply stricter internal medical necessity rules than Original Medicare for services without a specific NCD or LCD. KFF found that 80.7 percent of appealed Medicare Advantage denials were overturned, which suggests many initial denials are avoidable if you appeal in 2026.
What is a Local Coverage Determination (LCD)?
A Local Coverage Determination is a coverage rule written by a regional Medicare Administrative Contractor that decides whether a specific service is reasonable and medically necessary in that MAC's service area. LCDs fill gaps where CMS has not issued a National Coverage Determination, which is why the same service can be covered in one state and denied in another under Original Medicare in 2026.
How long do I have to appeal a Medicare denial in 2026?
You have 120 days from the date on your denial notice to file a Level 1 Redetermination Request with your Medicare Administrative Contractor. If that is denied, you have 180 days to request a Level 2 Reconsideration from a Qualified Independent Contractor, then 60 days for each further level, including the Administrative Law Judge hearing and Medicare Appeals Council.
Does Medicare Part D deny prescription drug coverage?
Yes. Part D plans deny a drug when it is not on the formulary, when step therapy requires trying a cheaper drug first, or when the prescribed quantity exceeds the plan's limit. Part D plans must decide a standard coverage determination within 72 hours and an expedited request within 24 hours in 2026, and your doctor can request a formulary exception.
Can Medigap deny me coverage?
Medigap cannot deny an already-approved Original Medicare claim, because it only pays the cost-sharing Original Medicare leaves behind. Medigap insurers can deny you a new policy or charge more based on your health if you apply outside your six-month Medigap Open Enrollment Period, which starts the month you turn 65 and enroll in Part B.
What happens if my Medicare appeal is denied at every level?
If the Medicare Appeals Council upholds the denial, you can file in U.S. District Court within 60 days, as long as the disputed amount reaches $1,960 in 2026. If your case does not meet that dollar threshold, a free State Health Insurance Assistance Program (SHIP) counselor can help you review remaining options, including standalone supplemental coverage for the denied service.
Is the Medicare Advantage prior authorization process changing in 2026?
Yes. The CMS Interoperability and Prior Authorization Final Rule (CMS-0057-F) requires every Medicare Advantage plan to decide standard prior authorization requests within 7 calendar days and expedited requests within 72 hours starting January 1, 2026, and to state a specific reason for each denial instead of a generic one. The rule also requires more transparency about which services need prior authorization.
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