2026 ICD-10-CM Diagnosis Code A81.2Progressive multifocal leukoencephalopathy

ICD-10-CM Codes›A00–B99›A80-A89›A81

ICD-10-CM A81.2
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A81.2 is a billable ICD-10-CM diagnosis code for progressive multifocal leukoencephalopathy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 974 through 976. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified CNS infection and poliomyelitis and Viral infection.

Code Identity

ICD-10-CM Code
A81.2
Billable Status
Yes — Valid for Submission
Code Describes
Progressive multifocal leukoencephalopathy
Short Description
Progressive multifocal leukoencephalopathy
Same as the full description in the CMS dataset.
Parent Code
A81
Atypical virus infections of central nervous system

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA80-A89Viral and prion infections of the central nervous system
CategoryA81Atypical virus infections of central nervous system
This CodeA81.2Progressive multifocal leukoencephalopathy

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Central nervous system demyelinating disease with AIDS
  • Cerebral degeneration due to progressive multifocal leukoencephalopathy
  • Dementia with progressive multifocal leukoencephalopathy
  • Demyelinating disease of central nervous system co-occurrent with human immunodeficiency virus infection
  • Disease caused by JC polyomavirus
  • Encephalopathy with AIDS
  • Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation
  • Progressive multifocal leukoencephalopathy
  • Progressive multifocal leukoencephalopathy co-occurrent with human immunodeficiency virus infection
  • Progressive multifocal leukoencephalopathy with AIDS
  • White matter disorder caused by infection

Tabular List NotesGuidance

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

Inclusion Terms

  • Multifocal leukoencephalopathy NOS

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.

    • Leukoencephalopathy
      • multifocal (progressive)
    • Leukoencephalopathy
      • progressive multifocal

Clinical ClassificationClinical

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

CCSR NVS003
Other specified CNS infection and poliomyelitis
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INF008
Viral infection
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

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

Convert A81.2 to ICD-9-CMHistory

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

ICD-9-CM
046.3 Prog multifoc leukoencep
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 A81.2Overview

Is A81.2 (Atypical virus infections of central nervous system) a billable code?

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

What MS-DRG does A81.2 group to?

When progressive multifocal leukoencephalopathy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 974, 975, 976, with relative weights from 0.8945 to 2.8860 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A81.2?

Under the General Equivalence Mappings, progressive multifocal leukoencephalopathy converts to ICD-9-CM 046.3 (prog multifoc leukoencep). 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.