N18.4 — Chronic kidney disease, stage 4 (severe)
N18.4 is a billable, specific ICD-10-CM code for chronic kidney disease, stage 4 (severe). It is valid for submission on a claim.
Risk adjustment
N18.4 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 327 Chronic Kidney Disease, Severe (Stage 4)0.514 RAF
Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.
Medicare coverage
N18.4 is named in 53 Medicare coverage policies — 53 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A52996Billing and Coding: Routine Foot Care
- A55336Billing and Coding: Retroperitoneal Ultrasound
- A56232Billing and Coding: Foot Care
- A56416Billing and Coding: Assays for Vitamins and Metabolic Function
How N18.4 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to N18.4.
- Disease, diseased›kidney›chronic›stage 4(severe)
There’s a guided path to this code
Not sure N18.4 is the right one? Answer a few questions about what the chart documents and we’ll walk you to the code that follows from it.
Related codes at this level
Codes that share N18. If N18.4 is not quite right, the correct code is usually one of these.
Questions about N18.4
- Is N18.4 a billable ICD-10-CM code?
- Yes. N18.4 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does N18.4 sit in the tabular list?
- Diseases of the genitourinary system (N00-N99), in the block Acute kidney failure and chronic kidney disease (N17-N19).