Question 1

What is ICD-10 code N01.5?

Accepted Answer

N01.5 is the ICD-10-CM diagnosis code for rapidly progressive nephritic syndrome with diffuse mesangiocapillary glomerulonephritis. A rapidly worsening kidney condition involving both cell proliferation and membrane thickening in the filtering units, causing significant protein loss and kidney damage. N01.5 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering glomerular diseases (n00-n08).

N01.5 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.

Mesangiocapillary (membranoproliferative) pattern requires biopsy confirmation with both light and electron microscopy.

Question 2

Is N01.5 an HCC code?

Accepted Answer

No. N01.5 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 N01.5 billable?

Accepted Answer

Yes. N01.5 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. N01.5 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 N01.5 map to under V28?

Accepted Answer

N01.5 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 N01.5?

Accepted Answer

N01.5 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 N01.5?

Accepted Answer

N01.5 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 N01.5 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 N01.5?

Accepted Answer

Mesangiocapillary (membranoproliferative) pattern requires biopsy confirmation with both light and electron microscopy Document any associated secondary causes such as infections, autoimmune disease, or complement abnormalities N01.5 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.

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N01.5

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N01.5 ICD-10-CM Code: Rapidly progressive nephritic syndrome with diffuse mesangiocapillary glomerulonephritis

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N01.5

Is N01.5 an HCC code?

Get the V28 mapping + MEAT cheat sheet

What This Code Means

Coding Tips

Excludes 1, Do NOT code together

Child Codes

Code Hierarchy

Work N01.5 in HCC Buddy