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N03.5 ICD-10-CM Code: Chronic nephritic syndrome with diffuse mesangiocapillary glomerulonephritis

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

N03.5

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

Chronic nephritic syndrome with diffuse mesangiocapillary glomerulonephritis

A long-term kidney disease involving inflammation and damage to both the mesangial cells and the capillary walls of the kidney's filtering units.

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
N03Chronic nephritic syndrome
N03.5Chronic nephritic syndrome with diffuse mesangiocapillary glomerulonephritis

Inclusion Terms

Official
  • Chronic nephritic syndrome with membranoproliferative glomerulonephritis, types 1 and 3, or NOS

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for N03.5 in this effective period.

Related Child Codes

Official
N03.0Chronic nephritic syndrome with minor glomerular abnormality
N03.1Chronic nephritic syndrome with focal and segmental glomerular lesions
N03.2Chronic nephritic syndrome with diffuse membranous glomerulonephritis
N03.3Chronic nephritic syndrome with diffuse mesangial proliferative glomerulonephritis
N03.4Chronic nephritic syndrome with diffuse endocapillary proliferative glomerulonephritis

Includes

Official
  • chronic glomerular disease
  • chronic glomerulonephritis
  • chronic nephritis

Excludes 1

Official
  • Chronic nephritic syndrome with C3 glomerulonephritis (N03.A)
  • Chronic nephritic syndrome with C3 glomerulopathy (N03.A)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for N03.5 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for N03.5 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for N03.5 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Mesangiocapillary (membranoproliferative) pattern must be documented in pathology findings
This is a more complex kidney disease pattern requiring careful documentation review

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 N03.5 an HCC code?

No. N03.5 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

Code
N03.5
Description
Chronic nephritic syndrome with diffuse mesangiocapillary 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

N03.5 is the ICD-10-CM diagnosis code for chronic nephritic syndrome with diffuse mesangiocapillary glomerulonephritis. A long-term kidney disease involving inflammation and damage to both the mesangial cells and the capillary walls of the kidney's filtering units. N03.5 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering glomerular diseases (n00-n08).

N03.5 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.

Mesangiocapillary (membranoproliferative) pattern must be documented in pathology findings.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N03.5 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • Mesangiocapillary (membranoproliferative) pattern must be documented in pathology findings
  • This is a more complex kidney disease pattern requiring careful documentation review

Excludes 1, Do NOT code together

  • Chronic nephritic syndrome with C3 glomerulonephritis (N03.A)
  • Chronic nephritic syndrome with C3 glomerulopathy (N03.A)

Child Codes

Code Hierarchy

N03Chronic nephritic syndromeN03.5Chronic nephritic syndrome with diffuse mesangiocapillary glomerulonephritis
N03.5Chronic nephritic syndrome with diffuse mesangiocapillary glomerulonephritis

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