N18.9 ICD-10-CM Code: Chronic kidney disease, unspecified
HCC Buddy Code Card
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FY 2026 Apr update / Diseases of the genitourinary system (N00-N99) / Acute kidney failure and chronic kidney disease (N17-N19)
N18.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceChronic kidney disease, unspecified
Chronic kidney disease of unspecified stage indicates long-term kidney damage where the specific severity level has not been determined or documented.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Chronic renal disease
- Chronic renal failure NOS
- Chronic renal insufficiency
- Chronic uremia NOS
- Diffuse sclerosing glomerulonephritis NOS
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for N18.9 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for N18.9 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for N18.9 in this effective period.
Code First
Official- any associated:
- diabetic chronic kidney disease (E08.22, E09.22, E10.22, E11.22, E13.22)
- hypertensive chronic kidney disease (I12.-, I13.-)
Use Additional
Official- code, if applicable, to identify:
- associated cachexia (E88.A)
- kidney transplant status (Z94.0)
Code Also
OfficialICD-10-CM does not list Code Also instructions for N18.9 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is N18.9 an HCC code?
No. N18.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- N18.9
- Description
- Chronic kidney disease, unspecified
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
N18.9 is the ICD-10-CM diagnosis code for chronic kidney disease, unspecified. Chronic kidney disease of unspecified stage indicates long-term kidney damage where the specific severity level has not been determined or documented. N18.9 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering acute kidney failure and chronic kidney disease (n17-n19).
N18.9 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Documentation references CKD without specifying stage. Query the provider whenever labs in the chart support a specific stage, N18.9 is the lowest-specificity option and carries no HCC.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N18.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Documentation references CKD without specifying stage. Query the provider whenever labs in the chart support a specific stage, N18.9 is the lowest-specificity option and carries no HCC.
- •Do not default to N18.9 when N18.30 or a stage-specific code is supportable. Unspecified CKD often points to provider narrative gaps that a retrospective review can close.
- •N18.9 does not map to a V28 payment HCC. The coder action here is to query for stage specificity in the chart, moving N18.9 to a documented stage 3 (N18.30-N18.32 → HCC 329/328) or higher is a tangible RAF capture.