2026 ICD-10-CM Diagnosis Code A81Atypical virus infections of central nervous system

ICD-10-CM Codes›A00–B99›A80-A89›A81

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

A81 is a non-billable ICD-10-CM category code for atypical virus infections of central nervous system, so it cannot be submitted on claims. Use a more specific code from this category instead, such as A81.00, A81.01, A81.09, and A81.1.

Code Identity

ICD-10-CM Code
A81
Billable Status
No — Non-Billable Category
Code Describes
Atypical virus infections of central nervous system
Chapter
A80-A89
Viral and prion infections of the 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 CodeA81Atypical virus infections of central nervous system

Specific Coding for Atypical virus infections of central nervous systemOverview

Non-specific codes like A81 require more characters. Use one of these billable codes instead:

  • A81.0 for Creutzfeldt-Jakob disease

  • Use A81.00 for Creutzfeldt-Jakob disease, unspecified

  • Use A81.01 for Variant Creutzfeldt-Jakob disease

  • Use A81.09 for Other Creutzfeldt-Jakob disease

  • Use A81.1 for Subacute sclerosing panencephalitis

  • Use A81.2 for Progressive multifocal leukoencephalopathy

  • A81.8 for Other atypical virus infections of central nervous system

  • Use A81.81 for Kuru

  • Use A81.82 for Gerstmann-Straussler-Scheinker syndrome

  • Use A81.83 for Fatal familial insomnia

  • Use A81.89 for Other atypical virus infections of central nervous system

  • Use A81.9 for Atypical virus infection of central nervous system, unspecified

Tabular List NotesGuidance

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

Includes

  • diseases of the central nervous system caused by prions

Use Additional Code

Patient EducationClinical

Neurologic Diseases

The brain, spinal cord, and nerves make up the nervous system. Together they control all the workings of the body. When something goes wrong with a part of your nervous system, you can have trouble moving, speaking, swallowing, breathing, or learning. You can also have problems with your memory, senses, or mood.

Read the full article at MedlinePlus

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

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 A81Overview

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

No. This is a category header that groups the codes for atypical virus infections of central nervous system, and headers cannot be submitted on claims. Claims for atypical virus infections of central nervous system need a more specific code from this category, such as A81.00, A81.01, and A81.09.