Medicare Outpatient Observation Status: Inpatient vs. Observation, the MOON and Your Appeal Rights

Under Original Medicare you are a hospital inpatient only from the moment a doctor writes an order admitting you. Before that order, you're an outpatient, even if you've spent two nights in a hospital bed with an IV in your arm. That one piece of paper decides whether the stay is billed under Part A or Part B, what you pay for the pills the nurse hands you, and whether Medicare will pay for a skilled nursing facility afterward.

The status hospitals use for "we're keeping you, but we haven't admitted you" is outpatient observation. Here's who decides it, the notice you're owed, what it costs with 2026 numbers, and the newer appeal right if you were admitted and then switched to observation.

Source: CMS 2026 Parts A and B fact sheet; 42 CFR 489.20(y); Medicare.gov, Skilled nursing facility care.

Who decides: the admission order and the two-midnight rule

Not you, and not really the hospital bed you're in. The federal rule is 42 CFR 412.3. For Part A to pay, you have to be "formally admitted as an inpatient" under an order from a physician or other qualified practitioner who has admitting privileges at that hospital and knows your case. The order has to be given at or before the time of admission, so your inpatient days start the day of the order, not the day you arrived.

Medicare.gov defines observation services as hospital outpatient services you get while your doctor decides whether to admit you or send you home. They can happen in the emergency department or in a regular unit upstairs. Nothing about the room tells you which status you're in.

The two-midnight rule. Since 2013, the regulation has told doctors when an admission is "generally appropriate" for Part A: when the admitting physician expects you to need hospital care that crosses two midnights. That expectation has to rest on medical factors (your history and other conditions, how severe the symptoms are, what you need right now, the risk of something going wrong) and those factors have to be written in the record. There are carve-outs:

• If you die or are transferred sooner than expected, the stay can still count as inpatient.
• Surgeries on Medicare's inpatient-only list can be inpatient no matter how long you stay.
• A doctor can admit you for a shorter expected stay, case by case, if the medical record supports it.

So the two-midnight rule is a guide for doctors, not a promise to you. Crossing two midnights in the building doesn't make you an inpatient. Only the order does.

Source: Medicare.gov, Inpatient or outpatient hospital status affects your costs (accessed Nov. 8, 2026).

Inpatient vs. observation: what you pay

People assume observation is always cheaper because it sounds less serious. Sometimes it is. Sometimes it isn't. Medicare's own change-of-status page says it plainly: depending on the Part B coinsurance you owe as an outpatient, your hospital bill may be lower or higher than the Part A deductible.

Source: CMS 2026 fact sheet; Medicare.gov, Inpatient hospital care; Medicare.gov, Outpatient hospital services; Medicare.gov, Skilled nursing facility care.

Three lines in that table cause most of the surprise bills.

The per-service copayment. Under observation, the hospital bills Part B line by line: the bed time, the lab work, the imaging, the IV drugs. Medicare.gov says the copayment for any one outpatient service generally can't be more than the Part A deductible ($1,736 in 2026), but the total for all of them can be. A short, simple observation stay usually costs less than the deductible. A long one with a lot of testing can cost more.

Critical access hospitals. If you're in a small rural hospital designated as a critical access hospital, Medicare.gov warns that your outpatient copayment may be higher and may even exceed the Part A deductible. Ask the business office whether the hospital has that designation.

Self-administered drugs. This is the one families never see coming. Part B generally doesn't cover the prescription and over-the-counter drugs you'd normally take yourself (your blood pressure pill, your statin), and many hospitals won't let you bring your own from home for safety reasons. So the hospital supplies them and bills you. If you have Part D, Medicare.gov says those drugs may be covered in some circumstances, but you'll likely pay first and then file a claim with your drug plan for a refund. Keep the itemized bill.

The MOON: your written warning

Hospitals can't keep you in observation indefinitely without telling you. 42 CFR 489.20(y), which carries out the federal NOTICE Act, requires hospitals and critical access hospitals to give a Medicare Outpatient Observation Notice (form CMS-10611, the "MOON") to anyone on Medicare who gets observation services as an outpatient for more than 24 hours.

Source: 42 CFR 489.20(y); CMS, FFS & MA MOON.

The written notice has to explain that you're an outpatient getting observation services and not an inpatient, the reason why, and what that means for your cost sharing and for whether Medicare will later cover skilled nursing facility care. CMS says hospitals must give the MOON to Medicare Advantage enrollees too.

Signing the MOON doesn't mean you agree with it. It only confirms you got it. What it does give you is a clear moment to ask the doctor: why observation, and what would it take to admit? If a skilled nursing stay is likely after this hospital visit, that conversation matters more than anything else on this page.

Why it matters for skilled nursing care

Original Medicare covers a skilled nursing facility (SNF) stay only after a medically necessary inpatient stay of at least 3 consecutive days, counting the day you're admitted as an inpatient and not counting the day you leave (42 CFR 409.30). Medicare.gov is explicit that time in observation or in the ER before admission doesn't count, even overnight. You also generally need to enter the SNF within 30 days of leaving the hospital.

That's where observation turns from a billing quirk into real money. Compare two hypothetical patients, each in the hospital for four nights and then needing 30 days of rehab in a SNF, all in 2026, with Original Medicare only.

Source: 42 CFR 409.30(a); Medicare.gov, Skilled nursing facility care; CMS 2026 fact sheet. Hypothetical computed by Maru Insurance.

The hospital bills may look about the same. The difference is what comes after. Patient 2 spent the same four nights in the same building with the same diagnosis, but two of those nights were observation, so Part A pays nothing toward the SNF. I won't put a dollar figure on "full charges" because it depends on the facility, but it is the facility's daily rate for every day, not $217 a day starting on day 21.

There are exceptions to the 3-day requirement. Medicare.gov names one for Original Medicare: if your doctor is part of an Accountable Care Organization approved for a SNF 3-Day Rule Waiver, the full stay may not be needed. Medicare Advantage plans may also waive it. Ask the hospital's case manager before you assume either applies. The whole SNF benefit, including benefit periods and discharge appeals, is in my post on Medicare skilled nursing facility coverage.

Admitted, then switched: your appeal right

Until recently, if a hospital admitted you and later reclassified you as an outpatient in observation, Medicare had no dedicated appeal process for it. That changed because of a federal court case, Alexander v. Azar. CMS published a final rule on October 15, 2024, effective October 11, 2024, that created appeal rights for people who were formally admitted and then changed to observation. The rules are at 42 CFR 405.1210 through 405.1212.

Who qualifies. Not everyone who gets switched. Under 405.1210 you have to meet all of these: you were formally admitted with an inpatient order; the hospital then reclassified you as an outpatient getting observation services; and either you didn't have Part B at the time, or you were in the hospital 3 or more consecutive days but were an inpatient for fewer than 3. Those last two conditions are the situations where the switch costs you the most: no Part B means you could owe the hospital's full outpatient charges, and fewer than 3 inpatient days means no SNF coverage.

The notice. For hospital stays on or after February 14, 2025, Medicare.gov says you should get a Medicare Change of Status Notice (CMS-10868) before you leave. The regulation says no later than 4 hours before release. It explains that the stay will be billed to Part B instead of Part A, that Medicare won't pay for a SNF afterward, and how to reach the Beneficiary and Family Centered Care Quality Improvement Organization (BFCC-QIO) for a fast appeal. If you think you qualify and don't get one, ask for it.

Source: 42 CFR 405.1210, 405.1211 and 405.1212; Medicare.gov, Appeal when a hospital changes your status (accessed Nov. 8, 2026).

If you win, Medicare.gov says you pay the Part A inpatient deductible ($1,736 in 2026) instead of Part B costs, and you may qualify for a Medicare-covered SNF stay within 30 days of discharge if you meet the other requirements. If you lose, you pay the Part B costs (or, without Part B, possibly the full outpatient bill), and Medicare won't cover a SNF stay afterward.

In Washington, the BFCC-QIO is Acentra Health, which handles Region 10. Its beneficiary helpline is 1-888-305-6759 (TTY 711). The number should also be on the notice you're handed.

Older stays. The rule also opened a look-back process for status changes going back to January 2009. Its 365-day filing window ended January 2, 2026. Medicare.gov says later requests are denied unless you show good cause for filing late. If your family paid for a SNF stay after a switch like this, a call to SHIBA costs nothing and can tell you whether a late request is worth trying. For how appeals work at every level beyond the QIO, see my post on the Medicare appeal process.

Medigap and Medicare Advantage

Medigap. Medicare Supplement plans are standardized by letter, so a given letter covers the same thing no matter who sells it. Here's how the three rows that matter for observation look in the CMS 2026 Medigap guide.

Source: CMS, Choosing a Medigap Policy (2026). Plans C and F are only available to people eligible for Medicare before January 1, 2020. Plan N pays the Part B coinsurance except copays of up to $20 for some office visits and up to $50 for ER visits that don't end in an inpatient admission.

The catch: Medigap helps pay your share of costs in Original Medicare. If Medicare doesn't cover the SNF stay because the 3-day requirement wasn't met, there's no Medicare SNF coinsurance for the policy to pick up. Washington's Medigap rules are covered in my post on Medigap in Washington and on our Medicare Supplement insurance in Washington page.

Medicare Advantage. Medicare.gov says if you're in a Medicare Advantage plan, your costs and coverage for hospital stays may be different, so check with your plan. You still get the MOON. The change-of-status appeal described above is the Original Medicare process; plan members should read their plan's Evidence of Coverage, ask the plan how it handles observation and the 3-day SNF requirement, and call the plan's member services before a planned surgery.

What to do in the hospital

None of this needs a lawyer at the bedside. It needs someone asking the right questions early.

1. Ask every day: "Is my mother an inpatient or an outpatient under observation?" Medicare.gov tells patients and caregivers to ask the doctor, a hospital social worker or a patient advocate each day.
2. If it's observation and rehab is likely, ask why. Ask the doctor what medical facts would support admission. You can't order an admission, but the doctor decides based on what's documented, and you can make sure the doctor has the full picture.
3. Read the MOON when it comes. Note the date and time. It's your proof of when observation started.
4. If you were admitted and then switched, ask for the Change of Status Notice and call Acentra Health at 1-888-305-6759 before you leave.
5. Bring a list of home medications, and after discharge, ask for an itemized bill so you can send the self-administered drug charges to your Part D plan.
6. Get unbiased help at no cost. SHIBA, the Washington Insurance Commissioner's Medicare counseling program, gives unbiased Medicare counseling at no cost, including understanding appeals: 800-562-6900, 8:30 a.m. to 4:30 p.m., Monday through Friday, or start at the OIC's SHIBA page. More on how SHIBA works in Washington.

One timing note. Every dollar figure here is a 2026 amount. CMS usually announces the next year's Part A and Part B deductibles in the fall; as of November 8, 2026 there's no 2027 fact sheet on the CMS newsroom. For the bigger picture of Parts A through D, see our Medicare in Washington page.

Questions

What is outpatient observation status in Medicare?

Observation services are hospital outpatient services you get while your doctor decides whether to admit you or send you home. Under Original Medicare they're billed under Part B, and you're an outpatient even if you spend the night in a hospital bed.

Who decides if I'm an inpatient or under observation?

Your doctor. You become an inpatient only when a qualified practitioner writes an order formally admitting you. Under the two-midnight rule, admission is generally appropriate when the doctor expects you to need hospital care that crosses two midnights.

Do observation days count toward the 3-day stay for skilled nursing coverage?

No. Original Medicare requires at least 3 consecutive inpatient days, not counting the discharge day. Time in observation or the ER before admission doesn't count, even overnight.

When does the hospital have to give me a MOON?

If you get observation services as an outpatient for more than 24 hours, the hospital must give you the Medicare Outpatient Observation Notice no later than 36 hours after observation began, or sooner if you're transferred, discharged or admitted.

Can I appeal if the hospital changed me from inpatient to observation?

Yes, if you qualify. For stays since February 14, 2025, you can ask the BFCC-QIO for a fast appeal if you were formally admitted, then reclassified, and either had no Part B or were in the hospital 3 or more days but an inpatient for fewer than 3. In Washington the BFCC-QIO is Acentra Health, 1-888-305-6759.

Federal Medicare rules, your plan's own documents and the facts of your hospital stay control what's covered. Confirm your situation with 1-800-MEDICARE, SHIBA, the BFCC-QIO or a licensed agent, and talk to an attorney for legal questions.

Sources

1. Medicare.gov: Inpatient or outpatient hospital status affects your costs
2. Medicare.gov: Inpatient hospital care
3. Medicare.gov: Outpatient hospital services
4. Medicare.gov: Skilled nursing facility care
5. CMS: 2026 Medicare Parts A and B premiums and deductibles fact sheet (Nov 14, 2025)
6. CMS Newsroom (checked Nov 8, 2026 for 2027 amounts)
7. eCFR: 42 CFR 412.3, admissions (two-midnight rule)
8. eCFR: 42 CFR 489.20(y), Medicare Outpatient Observation Notice
9. eCFR: 42 CFR 409.30, basic requirements for posthospital SNF care
10. eCFR: 42 CFR 405.1210, notice of appeal rights when reclassified to observation
11. eCFR: 42 CFR 405.1211, expedited determination procedures
12. eCFR: 42 CFR 405.1212, expedited reconsideration procedures
13. CMS: FFS & MA MOON (form CMS-10611)
14. Federal Register: Appeal Rights for Certain Changes in Patient Status, final rule (Oct 15, 2024)
15. Medicare.gov: Appeal when a hospital changes your status to outpatient getting observation services
16. Medicare.gov: Appealing a change in status during a hospital stay (retrospective appeals)
17. Acentra Health BFCC-QIO: Washington
18. Acentra Health BFCC-QIO: homepage (Region 10 helpline)
19. CMS: Choosing a Medigap Policy (2026)
20. Washington OIC: SHIBA free Medicare help