2026 ICD-10-CM Diagnosis Code N01.9Rapidly progressive nephritic syndrome with unspecified morphologic changes

ICD-10-CM Codes›N00–N99›N00-N08›N01

ICD-10-CM N01.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N01.9 is a billable ICD-10-CM diagnosis code for rapidly progressive nephritic syndrome with unspecified morphologic changes. 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 idiopathic rapidly progressive glomerulonephritis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nephritis; nephrosis; renal sclerosis.

Code Identity

ICD-10-CM Code
N01.9
Billable Status
Yes — Valid for Submission
Code Describes
Rapidly progressive nephritic syndrome with unspecified morphologic changes
Short Description
Rapidly progr nephritic syndrome w unsp morphologic changes
Parent Code
N01
Rapidly progressive nephritic syndrome

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN00-N08Glomerular diseases
CategoryN01Rapidly progressive nephritic syndrome
This CodeN01.9Rapidly progressive nephritic syndrome with unspecified morphologic changes

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Idiopathic rapidly progressive glomerulonephritis
  • Rapidly progressive glomerulonephritis
  • Rapidly progressive nephritic syndrome
  • Subacute 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.

    • Disease, diseased
      • glomerular
        • rapidly progressive
    • Disease, diseased
      • renal (functional) (pelvis)
        • rapidly progressive
    • Disease, diseased
      • renal (functional) (pelvis)
        • subacute
    • Glomerulonephritis
      • poststreptococcal NEC
        • rapidly progressive
    • Glomerulonephritis
      • rapidly progressive
    • Glomerulonephritis
      • subacute
    • Nephritis, nephritic(albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic)
      • poststreptococcal
        • rapidly progressive
    • Nephritis, nephritic(albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic)
      • rapidly progressive
    • Nephritis, nephritic(albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic)
      • subacute
    • Syndrome
      • nephritic
        • rapidly progressive

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

  • Subacute Glomerulonephritis

    a term that refers to glomerular damage resulting in hematuria, proteinuria, and azotemia. the histopathologic changes include rapidly progressive glomerulonephritis and membranoproliferative glomerulonephritis.

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 N01.9 to ICD-9-CMHistory

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

ICD-9-CM
580.4 Ac rapidly progr nephrit
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 N01.9Overview

Is N01.9 (Rapidly progressive nephritic syndrome) a billable code?

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

What MS-DRG does N01.9 group to?

When rapidly progressive nephritic syndrome with unspecified morphologic changes 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 N01.9?

Under the General Equivalence Mappings, rapidly progressive nephritic syndrome with unspecified morphologic changes converts to ICD-9-CM 580.4 (ac rapidly progr nephrit). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.