---
kind: "section"
citation: "42 C.F.R. § 412.620"
title: "42"
number: "412.620"
heading: "Patient classification system."
url: "https://uscodex.org/cfr/42/412.620"
---

# §412.620. Patient classification system.

- (a) **Classification methodology.**
  - (1) A patient classification system is used to classify patients in inpatient rehabilitation facilities into mutually exclusive case-mix groups.
  - (2) For purposes of this subpart, case-mix groups are classes of Medicare patient discharges by functional-related groups that are based on a patient's impairment, age, comorbidities, functional capabilities, and other factors that may improve the ability of the functional-related groups to estimate variations in resource use.
  - (3) Data from admission assessments under [§ 412.610(c)(1)](/cfr/42/412.610.md?p=c-1) are used to classify a Medicare patient into an appropriate case-mix group.
  - (4) Data from the discharge assessment under [§ 412.610(c)(2)](/cfr/42/412.610.md?p=c-2) are used to determine the weighting factors under [paragraph (b)(4)](#b-4) of this section.
- (b) **Weighting factors—**
  - (1) **General.** An appropriate weight is assigned to each case-mix group that measures the relative difference in facility resource intensity among the various case-mix groups.
  - (2) **Short-stay outliers.** We will determine a weighting factor or factors for patients that are discharged and not transferred (as defined in [§ 412.602](/cfr/42/412.602.md)) within a number of days from admission as specified by us.
  - (3) **Patients who expire.** We will determine a weighting factor or factors for patients who expire within a number of days from admission as specified by us.
  - (4) **Comorbidities.** We will determine a weighting factor or factors to account for the presence of a comorbidity, as defined in [§ 412.602](/cfr/42/412.602.md), that is relevant to resource use in the classification system.
- (c) **Revision of case-mix group classifications and weighting factors.** We may periodically adjust the case-mix groups and weighting factors to reflect changes in—
  - (1) Treatment patterns;
  - (2) Technology;
  - (3) Number of discharges; and
  - (4) **Other factors affecting the relative use of resources.**

## Notes

### Source

Source: 66 FR 41388, Aug. 7, 2001, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 1302 and 1395hh.

### Source

Source: 50 FR 12741, Mar. 29, 1985, unless otherwise noted.