Medicare Denied Inpatient Rehab: Rehab Hospital vs. Skilled Nursing

What This Means

Your plan is not saying no to rehab — it is saying no to which building: it has decided you do not need care in an inpatient rehabilitation facility (IRF — the “acute rehab” or rehabilitation hospital your doctors recommended) and that a skilled nursing facility (SNF) is enough. That is a level-of-care judgment, and Medicare’s own rules define the line (42 CFR 412.622): IRF care is for patients who need therapy from multiple disciplines, can tolerate an intensive program — generally at least 3 hours of therapy a day, 5 days a week, or in well-documented cases at least 15 hours across a 7-day week — and need a rehabilitation physician at bedside at least 3 days a week. If you are still in the hospital waiting on this decision, act today: have your doctor call the plan and request an expedited reconsideration — when a physician says the standard wait could seriously jeopardize your life, health, or ability to regain maximum function, the plan must grant the fast track (42 CFR 422.584) and decide within 72 hours (42 CFR 422.590(e)). The plan can extend that by up to 14 days, but only at your request or where the delay is in your interest, and it must tell you in writing.

If the denial instead arrived after the rehab stay — as a claim denial on an EOB (often CO-50 “not deemed a medical necessity” or CO-150 “level of service not supported”) — the fast track does not exist for payment disputes: you have 65 days from the date on a Medicare Advantage denial notice to file, and the plan then has up to 60 days to decide a payment reconsideration (42 CFR 422.590). With Original Medicare, follow your MSN: you have 120 days from receiving it (receipt is presumed 5 days after the date printed on it, and the MSN prints your exact deadline).

Not sure this is your situation? Broad “rehab denied” searches often land here when a neighboring guide is the better fit:

• Already in a SNF or rehab facility and coverage is ending with a Notice of Medicare Non-Coverage? That fast appeal runs on a different clock — see skilled nursing facility denied.
• Is the hospital pressing you to leave while the rehab question is unresolved? You have separate discharge appeal rights — see Medicare is discharging you too soon.
• Was the denial about observation status or the 3-day inpatient rule? See wrong level of care.

Why This Happens

• The plan read the record against the IRF criteria and picked the cheaper setting. Medicare Advantage plans review IRF admissions — usually through prior authorization — and the denial letter typically says intensive rehabilitation is “not medically necessary” or that care “can be safely provided at a lower level.” The named standard behind that language is 42 CFR 412.622(a)(3): multiple therapy disciplines, the intensive program (3 hours/day, 5 days/week, or 15 hours across the week in well-documented cases), medical stability to participate, and rehabilitation-physician supervision at least 3 face-to-face days a week.
• The documentation didn’t show tolerance for intensive therapy. The IRF’s preadmission screening — conducted, or updated, in the 48 hours before admission — must support a reasonable expectation that you meet every criterion. If hospital therapy notes show short or missed sessions, the plan reads that as “can’t tolerate 3 hours.”
• Your doctors certified it; the plan’s reviewer disagreed. Medicare requires your provider to certify you need intensive rehabilitation, continued medical supervision, and coordinated care (Medicare.gov) — but the plan’s own clinical reviewer makes the coverage call, and in 2024 Medicare Advantage plans denied 7.7% of prior authorization requests (KFF).
• Cost pressure is real on both sides of the fork. An IRF stay is hospital-level care billed under Part A; a SNF stay runs on its own cost structure ($0 for days 1–20, then $217 per day for days 21–100 in 2026). The settings are not interchangeable clinically — that is exactly what the appeal is about.

How Medicare Decides Between IRF and SNF

The fork comes down to one question: does the medical record show you need — and can participate in — the intensive program?

• IRF level (42 CFR 412.622(a)(3)): you require active therapy from multiple disciplines (physical, occupational, speech-language, or prosthetics/orthotics — at least one being PT or OT); you can reasonably be expected to participate in and benefit from at least 3 hours of therapy a day, 5 days a week (or, in well-documented cases, at least 15 hours in a 7-day week), with benefit shown by measurable, practical functional improvement; you are stable enough to participate; and you need a rehabilitation physician face-to-face at least 3 days a week. Therapy must begin within 36 hours from midnight of the admission day.
• SNF level (Medicare.gov): daily skilled nursing or therapy at a lower intensity, with no 3-hour benchmark — and in Original Medicare, its own gate: the 3-day qualifying inpatient hospital stay.
• Who decides what: in Original Medicare the treating team’s certification and the IRF’s preadmission screening drive the admission, and claims can be reviewed after the fact. In Medicare Advantage the plan decides up front — but MA plans must follow Traditional Medicare’s coverage conditions for basic benefits, and may apply their own internal coverage criteria only where Medicare’s criteria are not fully established, in which case those internal criteria must be publicly accessible and evidence-based (42 CFR 422.101(b)). For IRF admissions, Medicare’s criteria are written into regulation — so ask the plan to name exactly which 412.622 criterion it says you fail.

Should You Appeal?

What To Do Next

1. Get the denial in writing and find the stated reason. For a prior-authorization denial, the notice explains the clinical basis and your appeal rights. Ask the plan to identify the specific criterion it says you fail, and request the internal coverage criteria it applied — for basic benefits those must track Traditional Medicare’s rules, and any internal criteria must be publicly accessible (42 CFR 422.101(b)).
2. Still hospitalized? Request the expedited reconsideration now. You or any physician can make the request, orally or in writing, directly to the plan. When a physician indicates that waiting the standard timeframe could seriously jeopardize your life, health, or ability to regain maximum function, the plan must expedite and decide within 72 hours (42 CFR 422.584; 422.590). The hospital’s case manager can route it; your doctor’s supporting statement is the trigger that makes expedited review mandatory.
3. Build the criteria-by-criteria case. Ask your doctor for a letter addressing each 412.622 requirement, and ask the receiving IRF for its preadmission screening — the clinical evaluation, done or updated in the 48 hours before admission, that documents exactly the expectations the plan says are missing. Attach hospital therapy notes showing session tolerance.
4. If the hospital is pushing you out while you wait, use the discharge appeal. That is a separate fast appeal with its own deadline and reviewer — see Medicare is discharging you too soon.
5. If the denial came as a bill after the stay, file the standard appeal instead: within 65 days of the date on a Medicare Advantage notice (decision due within 60 days for payment requests), or by the deadline printed on your MSN for Original Medicare (120 days from receipt). The criteria-by-criteria evidence package is the same.
6. Get free help. Your State Health Insurance Assistance Program (SHIP) offers free counseling on Medicare appeals, or call 1-800-MEDICARE (1-800-633-4227).

Sources

• eCFR: 42 CFR 412.622 — IRF coverage criteria — multiple therapy disciplines, the intensive program (3 hours/day, 5 days/week, or 15 hours/week in well-documented cases), stability, rehabilitation-physician supervision 3 days/week, the 36-hour therapy start, and the 48-hour preadmission screening.
• Medicare.gov: Inpatient rehabilitation care — Part A coverage, the provider certification requirement, and 2026 benefit-period costs ($1,736 deductible; $434/day for days 61–90; $868/day lifetime reserve days; no second deductible after a direct transfer or admission within 60 days).
• Medicare.gov: Skilled nursing facility (SNF) care — the SNF side of the fork: the 3-day qualifying stay and 2026 cost-sharing ($0 days 1–20, $217/day days 21–100).
• eCFR: 42 CFR 422.584 — Expediting certain reconsiderations — who may request (any physician), the physician-supported mandate to expedite, and the exclusion of payment requests from the fast track.
• eCFR: 42 CFR 422.590 — Timeframes for reconsiderations — 30 days pre-service standard, 60 days payment, 72 hours expedited.
• eCFR: 42 CFR 422.101 — Requirements relating to basic benefits — MA plans must comply with Traditional Medicare coverage conditions; internal coverage criteria are allowed only where Medicare’s criteria are not fully established and must be publicly accessible and evidence-based.
• KFF: Medicare Advantage prior authorization determinations in 2024 — 7.7% of requests denied; 80.7% of appealed denials overturned; 11.5% of denials appealed.
• X12: Claim Adjustment Reason Codes (CARCs) — official definitions of CO-50 and CO-150.

Frequently Asked Questions