2026 ICD-10-CM Diagnosis Code M31.8Other specified necrotizing vasculopathies

ICD-10-CM Codes›M00–M99›M30-M36›M31

ICD-10-CM M31.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M31.8 is a billable ICD-10-CM diagnosis code for other specified necrotizing vasculopathies. 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
M31.8
Billable Status
Yes — Valid for Submission
Code Describes
Other specified necrotizing vasculopathies
Short Description
Other specified necrotizing vasculopathies
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 CodeM31.8Other specified necrotizing vasculopathies

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal blood test
  • Complement level below reference range
  • Demyelination due to systemic vasculitis
  • Drug-induced necrotizing vasculitis
  • Hypersensitivity reaction mediated by immune complex
  • Hypocomplementemic urticarial vasculitis
  • Interstitial lung disease due to systemic disease
  • Interstitial lung disease with systemic vasculitis
  • Necrotizing vasculitis of undetermined etiology
  • Necrotizing vasculitis secondary to connective tissue disease
  • Necrotizing vasculitis secondary to infection
  • Primary cutaneous vasculitis
  • Primary necrotizing systemic vasculitis
  • Rheumatoid necrotizing vasculitis
  • Small vessel vasculitis caused by immune complex
  • Systemic vasculitis
  • Vasculitis due to systemic disease

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Hypocomplementemic vasculitis
  • Septic vasculitis

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
        • specified NEC
    • Arteritis
      • necrosing or necrotizing
        • specified NEC
    • Vasculitis
      • hypocomplementemic
    • Vasculitis
      • systemic
    • Vasculopathy, necrotizing
      • specified NEC

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

  • Systemic Vasculitis

    a heterogeneous group of diseases characterized by inflammation and necrosis of the blood vessel walls.

Convert M31.8 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 M31.8Overview

Is M31.8 (Other necrotizing vasculopathies) a billable code?

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

What MS-DRG does M31.8 group to?

When other specified necrotizing vasculopathies 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 M31.8?

Under the General Equivalence Mappings, other specified necrotizing vasculopathies 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.