Question 1

What is ICD-10 code N01.8?

Accepted Answer

N01.8 is the ICD-10-CM diagnosis code for rapidly progressive nephritic syndrome with other morphologic changes. A rapidly progressive kidney disease with morphologic changes on biopsy that don't fit into the standard categories, causing inflammation and kidney function loss. N01.8 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering glomerular diseases (n00-n08).

N01.8 is a billable ICD-10-CM code, but the current payload does not show a mapping under the CMS-HCC V28, V24, ESRD, or RxHCC models. Do not assign risk adjustment value from this page when no source-backed mapping is shown; verify the applicable model and payment year.

Use this code only when the biopsy shows specific morphologic findings that don't match codes N01.1 through N01.7.

Question 2

Is N01.8 an HCC code?

Accepted Answer

No. N01.8 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 N01.8 billable?

Accepted Answer

Yes. N01.8 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. N01.8 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

Which HCC does N01.8 map to under V28?

Accepted Answer

N01.8 does not map to a CMS-HCC V28 payment category. Check the current CMS-HCC V28 model file for payment year 2026 rather than an older V24 tip sheet.

Question 5

What RAF reference is published for N01.8?

Accepted Answer

N01.8 has no separately stated V28 community reference coefficient. Check the current CMS mapping and factor files before using it in any member-score workflow.

Question 6

What is the V28 vs V24 difference for N01.8?

Accepted Answer

N01.8 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 community model rewards N01.8 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's V28/V24 community RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a community payment HCC.

Question 7

What documentation supports N01.8?

Accepted Answer

Use this code only when the biopsy shows specific morphologic findings that don't match codes N01.1 through N01.7 Document the specific morphologic findings in detail to justify the use of this 'other' category code N01.8 is not a CMS-HCC payment code, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

HCC Buddy Code Card

N01.8

Is N01.8 an HCC code?

Get the V28 mapping + MEAT cheat sheet

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Work N01.8 in HCC Buddy

N01.8 ICD-10-CM Code: Rapidly progressive nephritic syndrome with other morphologic changes

HCC Buddy Code Card

N01.8

Is N01.8 an HCC code?

Get the V28 mapping + MEAT cheat sheet

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Work N01.8 in HCC Buddy