IRF, SNF, or LTAC denied? We cite 42 CFR §412.622, the 60% Rule, and Jimmo v. Sebelius — and the insurer's own policy.

Why post-acute level-of-care denials are different

Post-acute level-of-care denials don't deny a procedure — they deny a place. An IRF admission, a SNF day, an LTAC stay, or simply the difference between inpatient and observation status. Each one represents thousands of dollars per day of care, and each one is now a flashpoint between Medicare Advantage plans (and commercial plans whose rules mirror them) and the federal regulations they're legally required to follow.

The good news: the federal rules are unusually specific and unusually patient-friendly. 42 CFR §412 Subpart P (IRF), 42 CFR §409 Subpart C and the CMS Medicare Benefit Policy Manual Chapter 8 (SNF), 42 CFR §412.23(e) (LTAC), and the Jimmo v. Sebelius Settlement (2013) collectively define a coverage standard that most insurer denials don't actually meet. A successful appeal turns the federal regulation back on the insurer's policy.

This guide walks through the most common denials for IRF, SNF, LTAC, and level-of-care downgrades — and the exact citations that overturn them.

CMS-4201-F: the most important rule change of the past five years

In April 2023, CMS issued a Final Rule (CMS-4201-F, effective January 1, 2024) that fundamentally changed Medicare Advantage post-acute denials. The rule:

• Requires MA plans to cover at least the same scope as Original Medicare — including LCDs, NCDs, the Medicare Benefit Policy Manual, and the IRF / SNF / LTAC PPS regulations.
• Prohibits MA plans from applying internal coverage criteria more restrictive than Original Medicare — i.e., MCG, InterQual, or proprietary criteria cannot override the federal regulations.
• Requires that MA plans applying internal criteria for non-covered or unspecified items follow specific transparency rules — and that internal criteria must be consistent with publicly available evidence.
• References the May 2023 Senate Finance Committee report documenting widespread inappropriate post-acute denials by MA plans.

For any Medicare Advantage IRF, SNF, or LTAC denial, cite CMS-4201-F directly. Many MA plans are still using pre-2024 internal criteria and are now overruled by their own regulator. The appeal letter should quote the rule.

The 60% Rule: read it carefully

42 CFR §412.29 (the IRF 60% Rule, formerly the 75% Rule) is one of the most-misapplied citations in IRF denials. It states that at least 60% of an IRF's total inpatient population must have one of 13 qualifying conditions:

1. Stroke

2. Spinal cord injury

3. Congenital deformity

4. Amputation

5. Major multiple trauma

6. Femur (hip) fracture

7. Brain injury

8. Neurological disorders (MS, MD, Parkinson's, polyneuropathy, ALS)

9. Burns

10. Active polyarticular RA / psoriatic arthritis / seronegative arthropathy

11. Systemic vasculitis with joint inflammation

12. Severe / advanced osteoarthritis (polyarticular involvement)

13. Hip / knee joint replacement (qualifying only if bilateral, BMI ≥50, OR age ≥85)

The 60% Rule applies to the facility's population, not the individual admission. This is the single most important point. An insurer denying an IRF admission because "the patient's diagnosis isn't on the 60% Rule list" is misapplying the regulation. An IRF can admit non-qualifying patients as long as 60% of its overall census meets the qualifying criteria. The individual admission must satisfy 42 CFR §412.622 — not §412.29.

That said, when the diagnosis IS on the qualifying list (stroke, hip fracture, brain injury, etc.), citing it explicitly strengthens the appeal because most denials raise the question.

42 CFR §412.622: the actual IRF admission criteria

The substantive IRF admission rule is 42 CFR §412.622(a)(3) and §412.622(a)(5). The patient must require AND tolerate the intensity of an IRF — not the level of care delivered at a SNF. Specifically:

1. Active, ongoing therapeutic intervention from multiple disciplines — at least two of: physical therapy, occupational therapy, speech-language pathology, prosthetics/orthotics.

2. Intensive rehabilitation program — generally 3 hours/day, 5 days/week OR 15 hours in 7 consecutive days (the latter accommodates patients who tolerate less per day but more cumulatively).

3. Reasonable expectation of significant practical improvement — OR demonstrated need for the intensity to maintain functional status (per Jimmo, see below).

4. Supervision by a rehabilitation physician with at least 3 face-to-face visits per week.

5. Interdisciplinary team approach — IDT meetings, coordinated plan of care.

Plus a Preadmission Screening (PAS) completed by a qualified clinician (typically a rehabilitation physician) within 48 hours of admission, establishing IRF appropriateness.

When an insurer denies IRF admission, the appeal must:

• Quote each criterion verbatim from §412.622.
• Document each criterion met, with chart references.
• Submit the PAS.
• Submit therapy tolerance data from the acute hospital (e.g., "patient tolerated 3.2 hr/day combined PT/OT/SLP at acute hospital prior to transfer").
• Submit Section GG admission scores (IRF-PAI) and FIM if used.

Jimmo v. Sebelius: the maintenance-therapy game-changer

In January 2013, the US District Court for Vermont approved the settlement in Jimmo v. Sebelius, a class-action case challenging CMS's de facto "improvement standard" for skilled care. The settlement:

• Required CMS to clarify that Medicare coverage for skilled nursing and skilled therapy services in SNF, home health, and outpatient therapy DOES NOT require improvement.
• Established that maintenance therapy IS skilled when the inherent complexity of the service requires the skills of qualified personnel.
• Required CMS to issue Manual revisions (CR 8458, January 2014) to remove improvement-standard language from the Medicare Benefit Policy Manual.

The CMS post-Jimmo revisions are in the Medicare Benefit Policy Manual Chapter 8, §§30.2 and 30.5 for SNF, and corresponding sections in Chapter 7 (home health) and Chapter 15 (outpatient therapy). The settlement explicitly applies to:

• SNF coverage — daily skilled service required, but improvement is NOT.
• Home health coverage — see the home-health vertical for full discussion.
• Outpatient therapy — Medicare Part B therapy.

For IRF, Jimmo's effect is nuanced — IRFs still require demonstrated rehab benefit, but maintenance to prevent functional decline now qualifies as long as the skilled-therapy intensity (3 hr/day) is medically necessary and the patient tolerates it.

The single most common SNF denial — "maintenance therapy / no improvement" — is post-Jimmo legally defective. Cite the case by name and year. Cite CR 8458. Quote the Manual.

SNF coverage: the daily skilled requirement plus 3-day stay

Medicare Part A covers SNF services for up to 100 days per spell of illness when:

1. The 3-day qualifying acute hospital stay is met (3 consecutive midnights as inpatient — observation does NOT count). Some MA plans waive the 3-day rule under value-based programs; check the plan-specific waiver.

2. A daily skilled service is required — skilled nursing OR skilled therapy. The service must require the skills of licensed professional personnel.

3. The service is provided in a Medicare-certified SNF.

4. The service is for a condition treated at the qualifying acute stay OR a related condition that arose during SNF care.

Skilled nursing examples (post-Jimmo): IV antibiotics, complex wound care (NPWT, multiple stages, surgical wounds), G-tube / NG management with complications, ostomy education and management, complex diabetes regimen requiring titration, complex pain management, intramuscular injections with monitoring, observation/assessment of unstable conditions.

Skilled therapy examples (post-Jimmo): restorative PT/OT/SLP after stroke or fracture; maintenance PT/OT/SLP for Parkinson's, MS, ALS, post-stroke chronic care when the complexity requires the skills of qualified personnel.

The custodial-care exclusion still applies — non-skilled assistance with ADLs alone is not covered. But the moment a patient requires daily skilled service, SNF coverage attaches.

SNF length-of-stay denials: the day-by-day battle

SNF day denials typically happen at days 14, 21, or 30. The insurer says: "patient has plateaued / no further improvement." The Jimmo counter:

• Submit the skilled service log for each disputed day. If skilled nursing or skilled therapy was required and delivered, the day is covered.
• Submit interim functional documentation — even small Section GG / FIM gains show ongoing benefit. Document daily progress notes.
• For maintenance therapy — document the clinical complexity that requires qualified personnel (e.g., dysphagia therapy with FEES adjustments, gait training with adaptive devices, vestibular retraining).
• Document discharge plan barriers — caregiver training incomplete, home safety eval pending, DME not delivered, transport for outpatient therapy unresolved. These are legitimate reasons to extend SNF days.

The Medicare 100-day cap is per spell of illness, not per year. A 60-day break in SNF / hospital care typically resets the spell.

LTAC admission: the 25-day rule and site-neutral exemption

Long-Term Acute Care Hospitals (LTAC, also LTCH) are paid under the LTCH-PPS at 42 CFR §412.500 et seq. The site-neutral payment system (introduced by the BBA of 2013 / IMPACT Act of 2014) requires LTAC patients to meet either of two criteria for LTCH-PPS payment (vs site-neutral acute-hospital rate):

1. >=8.5 ICU days at the acute referring hospital prior to LTAC transfer, OR

2. >=96 hours ventilator support at the acute referring hospital prior to LTAC transfer.

LTACs as a class must maintain an average length of stay >25 days (42 CFR §412.23(e)). This is the regulatory marker that distinguishes LTAC from regular acute hospitals.

Common LTAC patient profiles:

• Ventilator weaning — failed weaning at acute hospital, prolonged mechanical ventilation, weaning protocol with SBT/RSBI tracking.
• Complex wounds — multiple stage 3-4 pressure injuries, surgical dehiscence, NPWT requiring frequent changes, complex flap management.
• Prolonged IV antibiotics — osteomyelitis (typically 6-week courses), complex infections requiring monitoring.
• Complex medical management — multiple comorbidities, hemodialysis with multi-organ failure, complex infectious disease, post-surgical complications.

When an insurer denies LTAC admission, the appeal documents:

• The site-neutral exemption (ICU days, vent hours).
• The complex medical needs (vent wean protocol, wound documentation, IV antibiotic indication, monitoring requirements).
• The expected length of stay (>25 days typical).
• Why a SNF or IRF cannot manage the complexity.

For Medicare Advantage LTAC denials, cite CMS-4201-F. For commercial LTAC denials, cite the specific complex medical needs and the comparative inadequacy of SNF.

IRF → SNF downgrade: the multidisciplinary argument

The most common level-of-care dispute is "patient should go to SNF, not IRF." The IRF-specific advantages — and the basis for the appeal — are:

1. Multidisciplinary therapy at IRF intensity — 3 hr/day, 5 days/week from multiple disciplines. SNFs deliver less intensive therapy, often by single discipline at a time.

2. 24/7 rehab nursing — IRFs employ rehab-trained nurses (CRRN-certified often) who provide bowel/bladder retraining, transfer training, ADL retraining. SNF nursing is general nursing.

3. Daily physiatrist supervision — IRFs require >=3 face-to-face physiatrist visits/week. SNFs often have single attending visits/month.

4. Outcome data — Deutsch Med Care 2005 and Buntin Med Care 2010 documented better functional outcomes (FIM gain, return to community) for IRF vs SNF in moderate-severity stroke, hip fracture, and SCI populations.

5. AHA/ASA Guidelines for Adult Stroke Rehabilitation (Winstein Stroke 2016) explicitly recommend IRF for patients tolerating intensive therapy.

Submit Section GG / FIM admission scores demonstrating the intensive-therapy candidacy. Document that the patient cannot receive multidisciplinary therapy + 24-hr rehab nursing + physiatrist supervision at SNF level of care.

Two-Midnight Rule and inpatient → observation downgrades

Acute inpatient → observation downgrades are governed by the Two-Midnight Rule (42 CFR §412.3). Inpatient admission is supported when:

• The physician expects the patient to require >=2 midnights of medically necessary hospital care at the time of admission, OR
• The patient has had a procedure on the inpatient-only list, OR
• The "rare and unusual" exception applies — short-stay inpatient is reasonable based on physician judgment with documented rationale.

For inpatient denials retroactively converting to observation:

• Submit the admission H&P documenting expectation of >=2-midnight stay.
• Document the medical necessity rationale (e.g., need for telemetry, IV management, surgical observation).
• Cite physician's clinical judgment per the Two-Midnight Rule.
• For brief stays cite the "rare and unusual" exception with documented reason.

Pediatric IRF: rehab potential is rarely the question

Pediatric IRF admissions (children's rehabilitation hospitals, pediatric IRF units) face fewer 60% Rule challenges (most pediatric patients have qualifying conditions — TBI, SCI, congenital deformity, oncologic complications, multiple trauma, neurological disorders). The denials more often allege:

• "Outpatient therapy is sufficient" — rebuttable with multidisciplinary intensity argument and pediatric-specific developmental considerations.
• "Length of stay exceeds expected" — rebuttable with pediatric outcome data and ongoing developmental gain.

Cite the AAP Section on Physical Medicine and Rehabilitation positions and pediatric rehab outcome literature.

The peer-to-peer call: prepare the regulation citations

Medicare Advantage post-acute denials carry a 72-hour expedited appeal deadline if delay would jeopardize health. Standard appeals are 14 days.

For peer-to-peer:

• Demand a same-specialty reviewer — physiatrist for IRF, hospitalist or intensivist for LTAC, internist for SNF.
• Bring three things: the federal regulation citation (42 CFR §412.622, Jimmo, CMS-4201-F), the functional documentation (Section GG, FIM, therapy hours), and the insurer's own policy quote.
• For MA denials, lead with CMS-4201-F. Many MA medical directors are still applying pre-2024 internal criteria.

A note on letter length and tone

A post-acute level-of-care appeal should be 1.5 to 2 pages:

1. Header — member ID, claim #, level of care, dates of service / admission date.

2. Acute event + diagnosis — ICD-10, acute hospital course, transfer rationale, qualifying-condition mapping.

3. Functional assessment — Section GG, FIM, BIMS, Berg, Barthel, dysphagia status.

4. Therapy tolerance + multidisciplinary plan — hours/day, disciplines, physiatrist supervision.

5. Skilled service log (SNF) or complex medical needs (LTAC).

6. Address denial reason — quote insurer policy and federal regulation; map criteria met.

7. Closing — request overturn within deadline; cite CMS-4201-F for MA; demand peer-to-peer with same-specialty reviewer.

Tone is professional, regulatory, and firm. Quote the federal regulation and the Jimmo settlement by name. The medical director responds to citations and documentation.

When to escalate

If the first-level appeal fails:

• Original Medicare — Quality Improvement Organization (QIO) review for hospital discharges; Medicare Administrative Contractor (MAC) reconsideration; Qualified Independent Contractor (QIC) reconsideration; Administrative Law Judge (ALJ) hearing; Medicare Appeals Council; federal court.
• Medicare Advantage — Independent Review Entity (IRE / Maximus); ALJ hearing; Medicare Appeals Council; federal court.
• Self-funded ERISA plans — second-level internal appeal, then external review (binding under ACA §2719).
• Fully-insured commercial plans — state-mandated external review.
• Medicaid managed care — state Fair Hearing.

For Medicare Advantage post-acute denials, the IRE level (Maximus) is often where favorable decisions occur. Submit the same documentation with a renewed CMS-4201-F citation.

What good looks like

A successful post-acute level-of-care appeal letter:

• Quotes the controlling federal regulation by section (42 CFR §412.622, §412.29, §412.23(e), §409 Subpart C).
• Cites Jimmo v. Sebelius (2013) and CR 8458 for SNF maintenance-therapy denials.
• Cites CMS-4201-F (April 2023, effective January 2024) for Medicare Advantage denials.
• Submits Section GG admission scores, FIM if applicable, BIMS, Berg, Barthel.
• Documents therapy tolerance in hours/day with disciplines.
• Documents skilled service for SNF / complex medical needs for LTAC.
• Maps the diagnosis to 60% Rule qualifying conditions when applicable.
• Demands peer-to-peer with same-specialty reviewer (physiatrist / intensivist / internist).
• Stays within 2 pages.

Most post-acute denials reverse on first or second appeal when these elements are present. The federal regulations are unusually patient-friendly and unusually specific — once the documentation is structured around them, drafting the letter is mechanical.