Three Day Rule Medicare Skilled Nursing: Missouri Families Guide

What the Three-Day Rule Means for Your Family

Medicare Part A covers skilled nursing facility (SNF) rehabilitation — physical therapy, occupational therapy, skilled nursing care — after a hospital stay. But there is a strict prerequisite: the patient must have been formally admitted as an inpatient for at least three consecutive days before transferring to the SNF. The admission day counts, but the discharge day does not.

If your parent spent four nights in a Missouri hospital but was classified under observation status for any of those days, they may not meet the three-day requirement. Observation days do not count. Only days with a formal inpatient admission order qualify.

The financial consequences are immediate. Without a qualifying three-day stay, Medicare will not pay for SNF rehabilitation. Skilled nursing facility rates in Missouri typically range from $250 to $400 per day, and a 30-day rehabilitation stay could leave the family with a $7,500 to $12,000 bill that Medicare would have otherwise covered.

How to Verify Your Parent's Admission Status

Do not assume your parent has been admitted as an inpatient just because they are lying in a hospital bed. Request this information in writing from the hospital's admissions department or case manager within the first 24 hours of any hospitalization.

Ask specifically: "Is my parent classified as an inpatient or under observation status?" The answer determines everything that follows.

If the hospital delivers a Medicare Outpatient Observation Notice (MOON form), your parent is under observation. This triggers a conversation with the attending physician about whether the clinical situation warrants a conversion to inpatient status. The physician has the authority to change the classification if the patient's medical condition supports it.

Alexander v. Azar: The Legal Battle Over Observation Status

The Alexander v. Azar class-action lawsuit challenged Medicare's practice of counting observation days differently from inpatient days for the purpose of the three-day rule. The plaintiffs argued that patients who received hospital-level care under observation status were being unfairly denied SNF coverage based on a billing classification, not a clinical determination.

The case has moved through multiple courts and resulted in partial remedies, but the core three-day inpatient requirement remains in place as of 2026. Congress has not passed legislation to eliminate the observation status distinction for SNF coverage purposes.

For eligible Original Medicare patients who were first admitted as inpatients and then reclassified to observation while still in the hospital, Alexander v. Azar established a prospective appeal route using the Medicare Change of Status Notice (MCSN, CMS-10868). This does not remove the three-day rule; it gives eligible patients a way to challenge the classification before discharge. The MOON remains the separate notice of observation status and its implications.

Medicare Advantage and the Three-Day Rule

If your parent has a Medicare Advantage plan rather than Original Medicare, the three-day rule may not apply. Many Medicare Advantage plans have eliminated or modified the three-day inpatient requirement for SNF coverage, though specific rules vary by plan.

Check your parent's plan documents or call the member services number on their insurance card to confirm whether the plan enforces the three-day rule. If the plan has waived it, observation status does not block SNF coverage — but the plan may impose its own prior authorization requirements for SNF admission.

What to Do When the Three-Day Rule Is Not Met

If your parent was under observation for part of the hospital stay and does not meet the three-day inpatient requirement, the family has several options:

1. Use the prospective status-appeal route before discharge. Ask the attending physician and hospital to review the classification. If the hospital changed the status from inpatient to observation, ask for a Medicare Change of Status Notice (MCSN, CMS-10868) and use the prospective appeal route under Alexander v. Azar while your parent is still hospitalized.
2. Explore MO HealthNet (Medicaid) coverage. If your parent meets Missouri Medicaid financial eligibility requirements — countable assets under the applicable standard ($6,068.80 under the standard 209(b) category or $6,220.50 for cited waiver categories) — Medicaid can cover nursing facility care without the three-day inpatient requirement.
3. Appeal the observation classification. Use the prospective MCSN route under Alexander v. Azar while your parent is still hospitalized if eligible. For a past coverage dispute, pursue Medicare's applicable claims or status-appeal process.
4. Pay privately and then appeal. The family can pay for SNF care out of pocket while simultaneously appealing the coverage denial through Medicare's five-level appeal process.

The Missouri Hospital Discharge Guide includes a complete observation status verification checklist, physician conversation scripts, and the step-by-step process for challenging a coverage denial when the three-day rule blocks SNF access.

See more Missouri guides →