2026 ICD-10-CM Diagnosis Code M31.9Necrotizing vasculopathy, unspecified

ICD-10-CM Codes›M00–M99›M30-M36›M31

ICD-10-CM M31.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M31.9 is a billable ICD-10-CM diagnosis code for necrotizing vasculopathy, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 299 through 301. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Systemic lupus erythematosus and connective tissue disorders and Vasculitis.

Code Identity

ICD-10-CM Code
M31.9
Billable Status
Yes — Valid for Submission
Code Describes
Necrotizing vasculopathy, unspecified
Short Description
Necrotizing vasculopathy, unspecified
Same as the full description in the CMS dataset.
Parent Code
M31
Other necrotizing vasculopathies

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM30-M36Systemic connective tissue disorders
CategoryM31Other necrotizing vasculopathies
This CodeM31.9Necrotizing vasculopathy, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cryoglobulinemic vasculitis
  • Cutaneous complication of systemic sclerosis
  • Drug-induced necrotizing vasculitis
  • Lupus erythematosus-associated necrotizing vasculitis
  • Lupus vasculitis
  • Necrosis of artery
  • Necrotizing arteritis
  • Necrotizing cutaneous vasculitis
  • Necrotizing vasculitis
  • Necrotizing vasculitis due to mixed cryoglobulinemia
  • Necrotizing vasculitis secondary to connective tissue disease
  • Scleroderma-associated necrotizing vasculitis
  • Secondary systemic vasculitis
  • Small vessel vasculitis caused by immune complex
  • Vasculitis caused by drug

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.

    • Angiitis
      • necrotizing
    • Arteritis
      • necrosing or necrotizing
    • Vasculopathy, necrotizing

Clinical ClassificationClinical

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

CCSR MUS024
Systemic lupus erythematosus and connective tissue disorders
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR CIR037
Vasculitis
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Necrotizing Vasculitis

    a rare condition that involves inflammation and necrosis of the walls of the blood vessels; may occur in rheumatoid arthritis.

  • Necrotizing Arteritis

    an arteritis characterized by the presence of inflammation and necrosis in the arterial wall.

  • Overlap Necrotizing Arteritis

    a necrotizing arteritis that exhibits characteristic features of several distinct vascular disorders.

Convert M31.9 to ICD-9-CMHistory

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

ICD-9-CM
447.5 Necrosis of artery
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 M31.9Overview

Is M31.9 (Other necrotizing vasculopathies) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report necrotizing vasculopathy, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M31.9 group to?

When necrotizing vasculopathy, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 299, 300, 301, with relative weights from 0.7197 to 1.6327 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M31.9?

Under the General Equivalence Mappings, necrotizing vasculopathy, unspecified converts to ICD-9-CM 447.5 (necrosis of artery). 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.