Condition guide
Chronic Kidney Disease HCC Coding Guide
Chronic Kidney Disease (e.g. N18.5) maps to HCC 326 (Chronic Kidney Disease, Stage 5) under the CMS-HCC V28 risk adjustment model, with a community, non-dual, aged RAF weight of 0.815; V28 reached 100% phase-in for payment year 2026. N18.1, chronic kidney disease, stage 1, is non-HCC under V28. It can also map to HCC 327 (Chronic Kidney Disease, Severe (Stage 4)) and HCC 329 (Chronic Kidney Disease, Moderate (Stage 3, Except 3B)) when the documentation supports those manifestations.
Quick Facts
HCC Categories
HCC 326, Chronic Kidney Disease, Stage 5
HCC 327, Chronic Kidney Disease, Severe (Stage 4)
HCC 329, Chronic Kidney Disease, Moderate (Stage 3, Except 3B)
HCC 328, Chronic Kidney Disease, Moderate (Stage 3B)
RAF Weight Range
0.127 to 0.815
Community, non-dual, aged (V28)
Model
CMS-HCC V28 (PY2026, 100% phase-in)
6 ICD-10 codes map to payment HCCs
How coders write it
Chart notes, problem lists, and queries rarely spell out Chronic Kidney Disease. The shorthand you will actually see:
Whatever the note calls it, the payment question is the same: how the ICD-10-CM code resolves to a payment HCC.
What HCC category does Chronic Kidney Disease map to under V28?
Chronic kidney disease is a progressive condition affecting roughly 37 million US adults and is a meaningful driver of HCC risk adjustment scores. Under CMS-HCC V28, CKD maps to payment HCCs across a wider range of severity than coders often expect. Stage 5 falls in HCC 326 (community non-dual aged RAF about 0.815), severe stage 4 in HCC 327 (about 0.514), stage 3B in HCC 328 and the rest of stage 3 in HCC 329 (each about 0.127). Document the CKD stage from the most recent GFR, the underlying etiology, and any dialysis or functioning transplant status. The 3a versus 3B split matters in V28 because 3B routes to its own HCC, so specify it whenever the GFR supports it.
ICD-10 to HCC Mapping
| ICD-10 Code | Description | Billable | HCC Mapping |
|---|---|---|---|
| N18.4 | Chronic kidney disease, stage 4 (severe) | Yes | HCC 327 |
| N18.5 | Chronic kidney disease, stage 5 | Yes | HCC 326 |
| N18.6 | End stage renal disease | Yes | HCC 326 |
| N18.30 | Chronic kidney disease, stage 3 unspecified | Yes | HCC 329 |
| N18.31 | Chronic kidney disease, stage 3a | Yes | HCC 329 |
| N18.32 | Chronic kidney disease, stage 3b | Yes | HCC 328 |
| N18.1 | Chronic kidney disease, stage 1 | Yes | No HCC (not risk-adjusting under V28) |
| N18.2 | Chronic kidney disease, stage 2 (mild) | Yes | No HCC (not risk-adjusting under V28) |
| N18.9 | Chronic kidney disease, unspecified | Yes | No HCC (not risk-adjusting under V28) |
| Z99.2 | Dependence on renal dialysis | Yes | No HCC (not risk-adjusting under V28) |
RAF weights are community, non-dual, aged base coefficients from the CMS-HCC V28 model (PY2026). Verify against the latest CMS rate announcement for payment calculations.
HCC Buddy maps Chronic Kidney Disease from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coder workflow notes
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Documentation Tips
Always document the current CKD stage (1-5) based on the most recent GFR measurement, never code 'unspecified' when a stage is determinable.
Document the underlying cause of CKD (diabetic nephropathy, hypertensive nephrosclerosis, etc.) to capture additional HCC mappings.
When CKD is due to diabetes, use combination code E11.22 in addition to the N18 stage code.
Document dialysis status and modality (hemodialysis vs. peritoneal) when applicable.
Record the most recent eGFR value and date to support the documented CKD stage.
Document whether the patient has a functioning kidney transplant, which requires Z94.0 in addition to the CKD stage.
Note progression or stability of CKD compared to prior encounters to satisfy the 'Monitor' component of MEAT.
For CKD stage 3, specify 3a or 3b based on GFR to use the more specific ICD-10-CM codes.
MEAT documentation examples for Chronic Kidney Disease
A diagnosis only counts toward risk adjustment when the encounter note shows the provider engaged with it. These are the kinds of entries that satisfy the MEAT documentation standard for Chronic Kidney Disease:
MMonitor
“eGFR 38 today, down from 44 six months ago; recheck BMP in three months.”
“Urine ACR 340 mg/g, up from 180; nephrology follow-up moved up.”
“Home BP log reviewed: averaging 138/82 on lisinopril.”
EEvaluate
“Renal ultrasound: echogenic kidneys, no obstruction.”
“Medication list reviewed for renal dosing; NSAIDs held.”
“Anemia labs: hemoglobin 10.8, ferritin adequate, consistent with CKD anemia.”
AAssess
“CKD stage 3b secondary to diabetic nephropathy, progressing.”
“CKD stage 4, stable on current regimen; transplant evaluation discussed.”
“Hypertensive CKD, stage 3a, controlled.”
TTreat
“Started dapagliflozin 10 mg daily to slow CKD progression.”
“Lisinopril increased to 20 mg for proteinuria.”
“Referred to nephrology for stage 4 planning and access discussion.”
Common Coding Mistakes
Coding N18.9 (CKD, unspecified) when the medical record contains GFR values that clearly indicate a specific stage.
Failing to code the diabetic etiology (E11.22) alongside the CKD stage when diabetes is the documented cause.
Confusing ESRD (N18.6) with CKD stage 5 (N18.5), ESRD indicates the patient is on or being considered for renal replacement therapy.
Not updating the CKD stage when labs show progression from stage 3 to stage 4, missing the HCC capture opportunity.
V24 to V28 Changes
V28 reorganized CKD into stage-specific HCCs rather than the smaller set of broad categories used in the prior V24 model. Stage 5 now sits in HCC 326, severe stage 4 in HCC 327, stage 3B in HCC 328, and the remainder of stage 3 in HCC 329, each with its own recalibrated RAF weight. The headline change for coders is that the weights moved sharply: stage 4 went from 0.289 under V24 HCC 137 to 0.514 under HCC 327, and stage 5 from 0.289 under V24 HCC 136 to 0.815 under HCC 326. Stage 3 nearly doubled, from 0.069 to 0.127. One loss to know about: the dialysis status code Z99.2 paid its own V24 category (HCC 134, RAF 0.435) and carries no payment HCC in V28. Etiology codes still route to their own categories, so document both the stage and the underlying cause.
| Aspect | V24 (through PY2025) | V28 (PY2026) |
|---|---|---|
| Stage 3 and 3a (N18.30, N18.31) | HCC 138, CKD Moderate Stage 3, RAF 0.069 | HCC 329, Moderate Stage 3 Except 3B, RAF 0.127 |
| Stage 3b (N18.32) | HCC 138, same bucket as the rest of stage 3, RAF 0.069 | HCC 328, its own 3B category, RAF 0.127 |
| Stage 4 (N18.4) | HCC 137, RAF 0.289 | HCC 327, RAF 0.514 |
| Stage 5 and ESRD (N18.5, N18.6) | HCC 136, RAF 0.289 | HCC 326, RAF 0.815 |
| Dialysis status (Z99.2) | HCC 134, Dialysis Status, RAF 0.435 | No payment HCC |
RAF values are community, non-dual, aged base coefficients for each model's payment year. To see what these weights do to a real patient total, run the codes through the RAF score calculator.
Chronic Kidney Disease coding FAQs
Does CKD stage 3 risk-adjust under V28?
Yes. Stage 3a and unspecified stage 3 (N18.30, N18.31) map to HCC 329 and stage 3b (N18.32) maps to HCC 328, each with a community, non-dual, aged RAF weight of 0.127. Under V24 all of stage 3 shared HCC 138 at 0.069, so V28 nearly doubled the moderate-CKD weight. Stages 1 and 2 and unspecified CKD (N18.9) still carry no payment HCC.
What happened to the dialysis status code Z99.2 in V28?
It stopped paying. Z99.2 mapped to V24 HCC 134 (Dialysis Status) with a RAF weight of 0.435, and V28 dropped it from payment entirely. The risk-adjusting diagnoses for a dialysis patient are the CKD stage and ESRD codes themselves (N18.5, N18.6 to HCC 326), so make sure those are documented and captured each year.
Is N18.9 an HCC code?
No. Unspecified CKD (N18.9) carries no payment HCC under V28, even though staged CKD from 3a upward does. When the chart contains an eGFR that supports a stage, query or code the stage-specific N18 code instead of settling for N18.9.
Related Conditions
Related references
CMS-HCC V28 model
How the V28 categories, RAF weights, and hierarchy work for PY2026.
ICD-10 to HCC mapping
How an ICD-10-CM code resolves to a payment HCC under V28.
MEAT criteria
The documentation standard every coded condition must satisfy.
Add confirmed HCCs and review the full model total.
Sources
RAF weights are community, non-dual, aged base coefficients from the CMS-HCC V28 model (PY2026). Verify against the latest CMS Rate Announcement for payment.
Verified current to CMS-HCC V28, payment year 2026 — last reviewed July 16, 2026.
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