Question 1

What is ICD-10 code N16?

Accepted Answer

N16 is the ICD-10-CM diagnosis code for renal tubulo-interstitial disorders in diseases classified elsewhere. Kidney disease affecting the tubules and interstitium that occurs as a complication of another disease classified elsewhere in the ICD-10 system. The kidney damage is secondary to another primary condition. N16 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering renal tubulo-interstitial diseases (n10-n16).

N16 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.

This code requires a secondary code to identify the underlying disease causing the kidney damage; always code both conditions.

Question 2

Is N16 an HCC code?

Accepted Answer

No. N16 is a billable ICD-10-CM code but does not map to any payment HCC category under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can still be reported on Medicare Advantage encounter data submissions, but it does not contribute to the beneficiary's Risk Adjustment Factor (RAF) score and therefore does not affect the risk-adjusted capitation payment to the plan. V28 reached 100% phase-in for payment year 2026.

Question 3

Is N16 billable?

Accepted Answer

Yes. N16 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. N16 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Question 4

What is the V28 vs V24 difference for N16?

Accepted Answer

N16 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards N16 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

Question 5

What should coders know when reporting N16?

Accepted Answer

This code requires a secondary code to identify the underlying disease causing the kidney damage; always code both conditions Common underlying conditions include diabetes, systemic lupus erythematosus, and infections; ensure the primary condition is documented and coded

N16

Is N16 an HCC code?

What This Code Means

Coding Tips

Excludes 1 — Do NOT code together

Code First

Code Hierarchy

Open N16 in the Interactive Encoder