ICD-10 · PDGM grouping
N21 Calculus of lower urinary tract
All 4 codes in the N21 family, with the PDGM clinical group, comorbidity subgroup and primary-position rule CMS assigns, read from the CMS grouper crosswalk v07.2.26 and the CDC FY2027 code file.
Codes in family
4
Can lead a claim
3
Cannot lead a claim
1
What CMS assigns to N21
3 of the 4 codes group to MMTA - Gastrointestinal tract and Genitourinary system; 1 is assigned no clinical group. None of the 4 is assigned a comorbidity subgroup. 3 of the 4 can lead a claim.
Every code in N21
Descriptions are CDC’s FY2027 wording; where CMS’s grouper abbreviates one, its form is shown beneath.
| Code | Description | Primary position | Clinical group | Comorbidity subgroup |
|---|---|---|---|---|
| N21.0 | Calculus in bladder | Can lead a claim | J | None |
| N21.1 | Calculus in urethra | Can lead a claim | J | None |
| N21.8 | Other lower urinary tract calculus | Can lead a claim | J | None |
| N21.9 | Calculus of lower urinary tract, unspecified | Cannot lead a claimPrincipal diagnosis not assigned to a clinical group | None | None |
Sources: CMS HH PPS Grouper Software v07.2.26, effective 2026-10-01, for the clinical group, comorbidity subgroup, code-first conventions and primary-position flags; CDC NCHS ICD-10-CM FY2027 code descriptions for the family title and code wording. This is the crosswalk Medicare runs a claim through. Grouping also depends on admission source, timing, the OASIS functional items and the rest of the diagnosis list.
The monthly home health regs digest
What CMS changed, what's due next, and what to do about it — one email a month, no fluff. Read the first issue