Guide · Long-Term Care
LTCH Short-Stay & Interrupted-Stay
Two case-level rules that adjust how an LTCH stay is paid: the short-stay outlier for stays that end early, and the interrupted-stay policy that treats a leave-and-return as a single stay.
No PHIReferenceInformational reference — paraphrased from CMS rules and manuals, not billing or legal advice; verify against 42 CFR 412.529, 42 CFR 412.531, and your MAC.
Short-stay outlier (SSO)
42 CFR 412.529An SSO applies when the covered length of stay is from one day up to and including five-sixths (⅚) of the geometric average length of stay for the case's MS-LTC-DRG. Above that threshold, the case is paid the full MS-LTC-DRG amount.
| Trigger | covered LOS ≤ ⅚ of the MS-LTC-DRG geometric average |
| Paid as | the least of several amounts — generally 100% of estimated cost; 120% of the MS-LTC-DRG per-diem amount × covered days; the full MS-LTC-DRG payment; and an IPPS-comparable per-diem amount |
| Above threshold | full MS-LTC-DRG standard payment |
The exact set of amounts in the "least of" test is specified by rule and has changed over time; confirm the calculation for your discharge dates. The estimator flags when a case is likely a short-stay outlier rather than computing the reduced amount.
Interrupted stay — one payment
42 CFR 412.531When a patient leaves and returns to the same LTCH within the policy window, the LTCH receives a single MS-LTC-DRG (or adjusted SSO) payment for the whole stay. There are two forms.
| 3-day-or-less interruption | discharged to an acute hospital, IRF, or SNF — or home for up to 3 days — and readmitted within 3 days. The LTCH is responsible for the intervening services (under arrangements); days away are excluded from the length of stay unless treatment is provided. |
| Greater-than-3-day interruption | readmitted within a fixed-day window. The LTCH receives one payment for all portions; the acute hospital, IRF, or SNF is paid separately. Beyond the window, the return is treated as a new LTCH stay. |
| Discharge setting | Fixed-day window |
|---|---|
| Acute care hospital | up to 9 days |
| Inpatient rehabilitation facility (IRF) | up to 27 days |
| Skilled nursing facility (SNF) | up to 45 days |
Counting begins on the day of discharge from the LTCH. Interrupted-stay cases can still qualify for a high-cost outlier; the day-counting rules are precise — verify.
