2026 ICD-10-CM Diagnosis Code N05.3Unspecified nephritic syndrome with diffuse mesangial proliferative glomerulonephritis

ICD-10-CM Codes›N00–N99›N00-N08›N05

ICD-10-CM N05.3
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N05.3 is a billable ICD-10-CM diagnosis code for unspecified nephritic syndrome with diffuse mesangial proliferative glomerulonephritis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 698 through 700. Coders also document this condition as IgM nephropathy. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nephritis; nephrosis; renal sclerosis.

Code Identity

ICD-10-CM Code
N05.3
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified nephritic syndrome with diffuse mesangial proliferative glomerulonephritis
Short Description
Unsp neph syndrome w diffuse mesangial prolif glomrlneph
Parent Code
N05
Unspecified nephritic syndrome

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN00-N08Glomerular diseases
CategoryN05Unspecified nephritic syndrome
This CodeN05.3Unspecified nephritic syndrome with diffuse mesangial proliferative glomerulonephritis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • IgM nephropathy
  • Mesangial proliferative glomerulonephritis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Glomerulonephritis
      • diffuse
        • mesangial proliferative
    • Glomerulonephritis
      • mesangial
        • proliferative (diffuse) NEC
    • Nephritis, nephritic(albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic)
      • with
        • diffuse
          • mesangial proliferative glomerulonephritis

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR GEN001
Nephritis; nephrosis; renal sclerosis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Mesangial Proliferative Glomerulonephritis

    a focal inflammation of glomeruli secondary to mesangial cell proliferation and matrix deposition within the mesangium.

Patient EducationClinical

Kidney Diseases

You have two kidneys, each about the size of your fist. They are near the middle of your back, just below the rib cage. Inside each kidney there are about a million tiny structures called nephrons. They filter your blood. They remove wastes and extra water, which become urine. The urine flows through tubes called ureters.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert N05.3 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
583.2 Membranoprolif nephr NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About N05.3Overview

Is N05.3 (Unspecified nephritic syndrome) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified nephritic syndrome with diffuse mesangial proliferative glomerulonephritis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does N05.3 group to?

When unspecified nephritic syndrome with diffuse mesangial proliferative glomerulonephritis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 698, 699, 700, with relative weights from 0.6899 to 1.6544 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of N05.3?

Under the General Equivalence Mappings, unspecified nephritic syndrome with diffuse mesangial proliferative glomerulonephritis converts to ICD-9-CM 583.2 (membranoprolif nephr NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.