Original Medicare (Parts A and B)

Who this covers

This page is for people whose Medicare hospital and medical coverage comes straight from the federal government. If a private company runs your Medicare plan, see Medicare Advantage. If your denial is for a prescription drug, see Medicare drug plans. If you are not sure which coverage you have, try the coverage type finder.

If you are told your hospital stay, rehab, nursing care, home health or hospice care is ending

1. Find the notice. For a hospital stay it is the Important Message from Medicare. For skilled nursing, home health, rehabilitation or hospice care it is the Notice of Medicare Non-Coverage (Form CMS-10123, named for the Centers for Medicare & Medicaid Services). The provider must give you the second one no later than 2 days before covered services end.
2. Call the Quality Improvement Organization today. This is the independent Medicare reviewer. Its phone number is on the notice. If you cannot find the notice, call 1-800-MEDICARE (1-800-633-4227) and ask for the reviewer for your state.
3. Know your time limit. Hospital stay: ask no later than the day you leave. Skilled nursing, home health, rehabilitation or hospice care: ask by noon of the calendar day after you receive the notice. If the notice gives an earlier time, use the earlier one.
4. Ask for a fast appeal. You can ask by phone or in writing. Write down the date, the time and the name of the person you spoke to. If nobody answers, leave a message and note the time.
5. Know what happens next. The reviewer decides within one calendar day for a hospital stay, and within 72 hours of your request for the other services. A timely request also protects you from being billed for the extra days while the review runs.
6. If you miss the time. A late request is still reviewed, but without the fast deadline or the protection from charges. Call anyway.

See the fast appeals guide for a worked date example and the phone script for a fast Medicare appeal.

How to tell this is your coverage

Look at the notice you received. A Medicare Summary Notice from Original Medicare says it is not a bill and explains how to ask for a first appeal, which Medicare calls a redetermination. Medicare Summary Notices come on paper every 6 months, and electronic notices are available monthly. The 120 days run from receiving the notice, so checking your claims in your online Medicare account lets you see decisions sooner.

If a hospital or care provider handed you a notice just before care ended, use the fast appeal in the box above. Do not wait for the Medicare Summary Notice. Use the Medicare appeal navigator to see your steps, or read the five levels in more detail.

What does not apply to you

The rules for Medicare Advantage plans, Medicare drug plans and Medigap policies are different, and so are their deadlines. You do not wait for an insurer to forward your case to an independent reviewer: in Original Medicare you file each level yourself, inside its deadline. State appeal rights for private insurance, and state external review, do not apply.

Prior authorization (approval before care) has now reached part of Original Medicare. A pilot called the Wasteful and Inappropriate Service Reduction model has used it since 1 January 2026, and runs through 31 December 2031, for selected services such as skin substitutes, electrical nerve stimulator implants and knee arthroscopy for osteoarthritis, in New Jersey, Ohio, Oklahoma, Texas, Arizona and Washington. It does not apply to Medicare Advantage and does not change coverage rules. The federal Centers for Medicare & Medicaid Services (CMS) page does not say how a request that is not approved under the pilot is appealed. Read the notice you receive, and call 1-800-MEDICARE if it does not say.

Where people go wrong

• Counting “60 days” for the first appeal. The first appeal in Original Medicare has 120 days. The 60-day figure belongs to later levels.
• Believing Medicare stops paying once you stop improving. It does not. Under a court settlement called Jimmo v. Sebelius, skilled nursing and skilled therapy can be covered to maintain your condition or slow decline, even if you are not improving.
• Missing the fast appeal. The hospital discharge and care-ending deadlines are measured in hours or days. A late request is still reviewed, but you lose the fast deadline and the protection from charges.
• Assuming observation status cannot be appealed. A person who was formally admitted and then switched to observation can appeal, if they had no Part B coverage then, or stayed in the hospital 3 or more consecutive days but were an inpatient for fewer than 3 days. A person who was never formally admitted cannot use this appeal. The window to appeal older stays closed on 2 January 2026. Read the observation status guide.
• Paying a provider who knew Medicare would deny. If neither you nor the provider knew, or could reasonably have been expected to know, that a service would be denied as not reasonable and necessary, Medicare can still pay. You are treated as knowing only if you were given written notice. A doctor who does not accept assignment generally has to refund money collected for such a service within 30 days of the denial notice, with exceptions. Ask your doctor’s office before you pay, and keep any form you signed.
• Going to court without checking the amount. A hearing needs at least $200 in dispute in 2026, and court needs at least $1,960.

Free help is listed above. You can also name someone to act for you with Form CMS-1696, Appointment of Representative.