N18.30
BillableChronic kidney disease, stage 3 unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is N18.30 an HCC code?
Yes. N18.30 maps to Pressure Ulcer of Skin with Necrosis Through to Muscle, Tendon, or Bone under the CMS-HCC V28 risk adjustment model (and Chronic Kidney Disease, Moderate (Stage 3) under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.
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.
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 Pressure Ulcer of Skin with Necrosis Through to Muscle, Tendon, or Bone (HCC 329) with a community, non-dual, aged base RAF weight of 1.071. 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 0.000. 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.
This unspecified code should only be used when the provider documentation does not differentiate between stage 3a (GFR 45-59) and 3b (GFR 30-44). 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
- •This unspecified code should only be used when the provider documentation does not differentiate between stage 3a (GFR 45-59) and 3b (GFR 30-44)
- •Query the provider or review lab values to determine if stage 3a or 3b can be assigned for greater specificity
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