N18.30 ICD-10-CM Code: Chronic kidney disease, stage 3 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)
N18.30
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceChronic kidney disease, stage 3 unspecified
Stage 3 chronic kidney disease with moderately decreased kidney function, but the specific substage (3a or 3b) is not specified.
Buddy Insight
Stage 3 chronic kidney disease unspecified represents moderate kidney function decline (GFR 30-59) without substage specification, indicating need for nephrology management and cardiovascular risk monitoring.
CMS-HCC V28
MappedHCC 329
RAF 0.127
CMS-HCC V24
MappedHCC 138
RAF 0.069
ACA/HHS
N/A—
Not mapped
ESRD/PACE
MappedHCC 138
RAF 0.000
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for N18.30 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for N18.30 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for N18.30 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for N18.30 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for N18.30 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for N18.30 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for N18.30 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 N18.30 an HCC code?
Yes. N18.30 (Chronic kidney disease, stage 3 unspecified) maps to Chronic Kidney Disease, Moderate (Stage 3, Except 3B) under the CMS-HCC V28 risk adjustment model (and Chronic Kidney Disease, Moderate (Stage 3) under V24), with a community non-dual aged RAF of 0.127. It is billable for payment year 2026.
Coder answer: N18.30 is billable and maps to V28 HCC 329, Chronic Kidney Disease, Moderate (Stage 3, Except 3B). Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- N18.30
- Description
- Chronic kidney disease, stage 3 unspecified
- HCC (V28)
- HCC 329 — Chronic Kidney Disease, Moderate (Stage 3, Except 3B)
- RAF
- 0.127
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
Work N18.30 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for N18.30
For N18.30 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed N18.30 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
N18.30 is the ICD-10-CM diagnosis code for chronic kidney disease, stage 3 unspecified. Stage 3 chronic kidney disease with moderately decreased kidney function, but the specific substage (3a or 3b) is not specified. N18.30 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).
Under the CMS-HCC V28 risk adjustment model, N18.30 maps to Chronic Kidney Disease, Moderate (Stage 3, Except 3B) (HCC 329) with a community, non-dual, aged base RAF weight of 0.127. Under the older CMS-HCC V24 model, N18.30 maps to Chronic Kidney Disease, Moderate (Stage 3) (HCC 138) with a community, non-dual, aged base RAF weight of 0.069. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Provider must document CKD stage 3 when the specific sub-stage (3a vs 3b) is not specified. If both eGFR values (45-59 vs 30-44) are present in the chart, query the provider to confirm the sub-stage rather than defaulting to N18.30. Because N18.30 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N18.30 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Provider must document CKD stage 3 when the specific sub-stage (3a vs 3b) is not specified. If both eGFR values (45-59 vs 30-44) are present in the chart, query the provider to confirm the sub-stage rather than defaulting to N18.30.
- •Avoid N18.30 when N18.31 or N18.32 is supportable. Sub-stage specificity does change the HCC: stage 3 unspecified and 3a (N18.30/N18.31) map to HCC 329, while 3b (N18.32) maps to HCC 328. Query the provider when both eGFR ranges appear.
- •N18.30 maps to V28 HCC 329 (Chronic Kidney Disease, Moderate, Stage 3 Except 3B) at RAF 0.127. Under V28, CKD begins risk-adjusting at stage 3, not stage 4; only stage 1-2 and unspecified CKD carry no HCC.
Clinical Significance
Stage 3 chronic kidney disease unspecified represents moderate kidney function decline (GFR 30-59) without substage specification, indicating need for nephrology management and cardiovascular risk monitoring. This diagnosis has varying HCC impacts across models and requires careful substage documentation for optimal coding.
Documentation Requirements
- ✓Chronic kidney disease stage 3 clearly documented
- ✓GFR values in the 30-59 range supporting stage 3
- ✓Documentation of why substage 3a or 3b is not specified
- ✓Underlying etiology of CKD if known
- ✓Current management plan including nephrology involvement
- ✓Cardiovascular risk assessment and management
- ✓Laboratory monitoring schedule documented