ICD-10-CM category N18
Chronic kidney disease (CKD): every N18 code with its CMS-HCC V28 status
N18, Chronic kidney disease (CKD), holds 11 codes in the FY2026 ICD-10-CM set: 9 billable codes and 2 header codes that need a further character. 6 of them maps to a CMS-HCC V28 payment category (HCC 326, 327, 328, and 329) for payment year 2026. The other 3 billable codes carry no V28 HCC and do not risk-adjust.
CMS-HCC V28 categories in N18 (4)
Coefficients are the code-level reference values from the CMS V28 factor file (community, non-dual, aged), not a member's score. Hierarchy, interactions, and enrollment segment decide what a documented condition contributes.
All 11 N18 codes (FY2026)
Descriptors are the FY2026 order-file text. Header codes need a further character and cannot be reported; open any billable code for its tabular notes, MEAT guidance, and mapping detail.
| Code | Description | FY2026 | CMS-HCC V28 |
|---|---|---|---|
| N18 | Chronic kidney disease (CKD) | Header | Header code, not reportable |
| N18.1 | Chronic kidney disease, stage 1 | Billable | No V28 HCC |
| N18.2 | Chronic kidney disease, stage 2 (mild) | Billable | No V28 HCC |
| N18.3 | Chronic kidney disease, stage 3 (moderate) | Header | Header code, not reportable |
| N18.30 | Chronic kidney disease, stage 3 unspecified | Billable | HCC 329 |
| N18.31 | Chronic kidney disease, stage 3a | Billable | HCC 329 |
| N18.32 | Chronic kidney disease, stage 3b | Billable | HCC 328 |
| N18.4 | Chronic kidney disease, stage 4 (severe) | Billable | HCC 327 |
| N18.5 | Chronic kidney disease, stage 5 | Billable | HCC 326 |
| N18.6 | End stage renal disease | Billable | HCC 326 |
| N18.9 | Chronic kidney disease, unspecified | Billable | No V28 HCC |
Documentation guides for N18
Frequently asked questions
How many N18 codes are there?
The N18 category (Chronic kidney disease (CKD)) has 11 codes in the FY2026 ICD-10-CM order file: 9 billable and 2 header codes, counting the category itself. Only a billable code can be reported on a claim.
Which N18 codes map to an HCC under CMS-HCC V28?
6 billable codes in N18 map to HCC 326, 327, 328, and 329 in the CMS-HCC V28 model for payment year 2026. HCC 326 (Chronic Kidney Disease, Stage 5) carries the most, with 2 codes. The 3 billable codes without a V28 category are marked "No V28 HCC" in the table.
Which N18 codes are not billable?
N18 itself and 1 subcategory code are header codes that need a further character before they can be reported: N18.3 (Chronic kidney disease, stage 3 (moderate)). Each one is listed in the table with the billable codes beneath it.
Source: FY2026 ICD-10-CM order file (FY 2026 Apr update) for codes, billability, and descriptors; CMS-HCC V28 PY2026 final ICD-10-CM mappings and relative factors for payment status. Table generated 2026-09-10.