Question 1

What is ICD-10 code N22?

Accepted Answer

N22 is the ICD-10-CM diagnosis code for calculus of urinary tract in diseases classified elsewhere. A kidney stone that develops as a complication of another disease, such as gout, hyperparathyroidism, or inflammatory bowel disease. N22 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering urolithiasis (n20-n23).

N22 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 diagnosis code for the underlying disease causing the stone.

Question 2

Is N22 an HCC code?

Accepted Answer

No. N22 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 N22 billable?

Accepted Answer

Yes. N22 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. N22 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 N22?

Accepted Answer

N22 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 N22 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 N22?

Accepted Answer

This code requires a secondary diagnosis code for the underlying disease causing the stone Always code the primary condition first, then N22 as a manifestation

N22

Is N22 an HCC code?

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