On April 27th CMS released the 2022 Inpatient Prospective Payment System (IPPS) proposed rule.[1] One of the most significant changes proposed for the V39 MS-DRG grouper logic includes changes to the severity level designation for unspecified codes. Recall for FY 2020, CMS proposed changes to the severity designation for 1,492 ICD-10-CM diagnosis codes which was postponed. The FY 2022 proposed rule includes a change to the severity level designation of the 3,490 “unspecified” diagnosis codes currently designated as either CC or MCC, where there are other codes available in the same code subcategory that further specify the anatomic site. According to the proposal, these 3,490 codes will change to a Non CC designation for FY 2022. CMS believes that changing the severity level for these “unspecified codes,” as compared to the more specific codes in the same subcategory, will leverage the additional specificity available in the ICD-10-CM system as it will foster reporting of the most specific diagnosis codes supported in medical record documentation. In this manner, CMS will incentivize more accurate, reliable and valid coded data.
The Table below provides a summary of the changes in severity level from the current V38.1 DRG grouper to the proposed FY22 V39 DRG grouper. These potential CC/MCC severity level changes would reduce the number of diagnosis codes on the CC/MCC list to 14,467.
Proposed FY22 Severity Level Changes
| Severity Level | V38.1 Number of Severity Level Codes | V39 Proposed Number of Severity Level Codes | Percent Change |
| MCC | 3,278 | 2,771 | -15.5% |
| CC | 14,679 | 11,696 | -20.3% |
| Non CC | 54,664 | 58,154 | 6.4% |
| Total | 72,621 | 72,621 | N/A |
Notably, several chapters in ICD-10-CM will see little or no impact from the proposed severity level changes, while other chapters would see a significant reduction in the number of CC/MCC codes.
While it is impossible to predict if the proposed severity level changes will be finalized for FY 22 it is notable that this type of comprehensive change has been discussed in the IPPS proposed and final rule for the past few years. So, if not in FY 2022, it is fairly certain that sweeping changes will be implemented at some point in the near future. After reviewing the detailed list of diagnosis codes [2], laterality appears to be critical. Codes that are currently designated as a CC or MMC with unspecified laterality will lose the CC/MCC severity designation. For example, the following stage 3 and 4 decubitus ulcer codes would no longer qualify as MCCs:
- Pressure ulcer of unspecified elbow, stage 3
- Pressure ulcer of unspecified elbow, stage 4
- Pressure ulcer of unspecified hip, stage 3
- Pressure ulcer of unspecified hip, stage 4
- Pressure ulcer of unspecified buttock, stage 3
- Pressure ulcer of unspecified buttock, stage 4
- Pressure ulcer of unspecified ankle, stage 3
- Pressure ulcer of unspecified ankle, stage 4
- Pressure ulcer of unspecified heel, stage 3
- Pressure ulcer of unspecified heel, stage 4
End Notes:
1. FY 2022 IPPS Proposed Rule Home Page | CMS
2. FY 2022 IPPS Proposed Rule Home Page | CMS, Table 6P.2a