ICD-10 N18.4
Billable / Specific HCC v28: 137 CCChronic kidney disease, stage 4 (severe)
About ICD-10-CM N18.4
ICD-10-CM code N18.4 represents Chronic kidney disease, stage 4 (severe). This is a billable/specific code in the Genitourinary System chapter (block N18). The 2026 edition of ICD-10-CM N18.4 became effective on October 1, 2025.
Coding Tips for N18.4
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
N18.4 is a CMS-HCC v28 risk-adjustment code (category 137). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
N18.4 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Chronic kidney disease, stage 4 (severe). As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for N18.4
Local Coverage Determinations (LCDs) from CMS MACs that list N18.4 as a covered diagnosis.
Showing top 10 of 366 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing N18.4.
1 Cigna
5 Medicare
CPT Codes Commonly Billed with N18.4
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 99215 Complex chronic disease management Internal Medicine
- 99215 Established patient — high complexity: HF exacerbation, COPD exacerbation, cancer management, MS, advanced CKD, uncontrolled diabetes, recurrent syncope, respiratory failure, liver cirrhosis Primary Care
- 80053 Comprehensive metabolic panel — diabetes, HTN, CKD, hyperlipidemia, electrolyte disorders, anemia, thyroid, prediabetes, abnormal labs, routine exam, screening Laboratory
- 82610 CMS LCD: Billing and Coding: Lab: Cystatin C Measurement CMS LCD
Convert N18.4 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| N18.4 | 5854 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To N18.4
Other codes in section N17-N19 (Acute kidney failure and chronic kidney disease).
ICD-10 N18.4, Billing FAQ
Is ICD-10 code N18.4 billable? +
Yes, N18.4 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does N18.4 affect Medicare Advantage HCC risk adjustment? +
Yes. N18.4 maps to CMS-HCC v28 category 137. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is N18.4 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with N18.4? +
Procedures frequently paired with N18.4 include: 99215, 99215, 80053, 82610.
What ICD-9 codes does N18.4 map to? +
Per CMS GEMs, N18.4 maps to ICD-9 codes: 5854. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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