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N01.A ICD-10-CM Code: Rapidly progressive nephritic syndrome with C3 glomerulonephritis

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FY 2026 Apr update / Diseases of the genitourinary system (N00-N99) / Glomerular diseases (N00-N08)

N01.A

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Rapidly progressive nephritic syndrome with C3 glomerulonephritis

A rapidly progressive kidney disease caused by abnormal activation of the complement system, leading to C3 protein deposits in the filtering units and rapid kidney damage.

CMS-HCC V28

N/A

Not mapped

CMS-HCC V24

N/A

Not mapped

ACA/HHS

N/A

Not mapped

ESRD/PACE

N/A

Not mapped

RXHCC

N/A

Not mapped

Code Book Path

Official
N01Rapidly progressive nephritic syndrome
N01.ARapidly progressive nephritic syndrome with C3 glomerulonephritis

Inclusion Terms

Official
  • Rapidly progressive nephritic syndrome with C3 glomerulopathy, NOS

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for N01.A in this effective period.

Related Child Codes

Official
N01.0Rapidly progressive nephritic syndrome with minor glomerular abnormality
N01.1Rapidly progressive nephritic syndrome with focal and segmental glomerular lesions
N01.2Rapidly progressive nephritic syndrome with diffuse membranous glomerulonephritis
N01.3Rapidly progressive nephritic syndrome with diffuse mesangial proliferative glomerulonephritis
N01.4Rapidly progressive nephritic syndrome with diffuse endocapillary proliferative glomerulonephritis

Includes

Official
  • rapidly progressive glomerular disease
  • rapidly progressive glomerulonephritis
  • rapidly progressive nephritis

Excludes 1

Official
  • Rapidly progressive nephritic syndrome (with C3 glomerulopathy) with dense deposit disease (N01.6)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for N01.A in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for N01.A in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for N01.A in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
C3 glomerulonephritis is confirmed by immunofluorescence showing isolated or dominant C3 deposits without significant immunoglobulin
Document complement levels (C3, C4) and consider testing for C3 nephritic factor or genetic complement abnormalities

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is N01.A an HCC code?

No. N01.A is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

Code
N01.A
Description
Rapidly progressive nephritic syndrome with C3 glomerulonephritis
HCC (V28)
No CMS-HCC V28 mapping
RAF
Billable
Yes
Payment year
2026

Coder workflow notes

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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).

What This Code Means

N01.A is the ICD-10-CM diagnosis code for rapidly progressive nephritic syndrome with c3 glomerulonephritis. A rapidly progressive kidney disease caused by abnormal activation of the complement system, leading to C3 protein deposits in the filtering units and rapid kidney damage. N01.A sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering glomerular diseases (n00-n08).

N01.A 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.

C3 glomerulonephritis is confirmed by immunofluorescence showing isolated or dominant C3 deposits without significant immunoglobulin.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N01.A sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • C3 glomerulonephritis is confirmed by immunofluorescence showing isolated or dominant C3 deposits without significant immunoglobulin
  • Document complement levels (C3, C4) and consider testing for C3 nephritic factor or genetic complement abnormalities

Excludes 1, Do NOT code together

  • Rapidly progressive nephritic syndrome (with C3 glomerulopathy) with dense deposit disease (N01.6)

Child Codes

Code Hierarchy

N01.A code history

Code setChange
FY2021 (effective Oct 1, 2020)Added to the code set

Source: official CMS ICD-10-CM order and addenda files, FY2016 through FY2027.

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