2026 ICD-10-CM Diagnosis Code A87.1Adenoviral meningitis

ICD-10-CM Codes›A00–B99›A80-A89›A87

ICD-10-CM A87.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A87.1 is a billable ICD-10-CM diagnosis code for adenoviral meningitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Meningitis and Viral infection.

Code Identity

ICD-10-CM Code
A87.1
Billable Status
Yes — Valid for Submission
Code Describes
Adenoviral meningitis
Short Description
Adenoviral meningitis
Same as the full description in the CMS dataset.
Parent Code
A87
Viral meningitis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA80-A89Viral and prion infections of the central nervous system
CategoryA87Viral meningitis
This CodeA87.1Adenoviral meningitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adenoviral meningitis
  • Adenoviral nervous system infection

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.

    • Meningitis(basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
      • adenoviral
    • Meningitis(basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
      • in (due to)
        • adenovirus

Clinical ClassificationClinical

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

CCSR NVS001
Meningitis
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INF008
Viral infection
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • GAIA Level 3a Neonatal Infectious Meningitis|Global Alignment of Immunization safety Assessment in pregnancy Level 3a Neonatal Infectious Meningitis|Level 3a Neonatal Bacterial/Fungal/Viral Meningitis

    gaia level 3a neonatal infectious meningitis is defined by four criteria: first, csf pleocytosis; second, no recognized pathogen is identified, using a validated method, from a normally sterile site; third, temperature greater than or equal to 37.5 degrees c or less than 35.5 degrees c; fourth, three or more of the following requirements must be met: a) history of convulsions; b) lethargy or irritability; c) coma; d) apnea; e) bulging fontanel; f) neck stiffness.

  • Viral Meningitis

    inflammation of the membranes surrounding the brain and spinal cord due to a viral infection.

Patient EducationClinical

Meningitis

Meningitis is inflammation of the thin tissue that surrounds the brain and spinal cord, called the meninges. There are several types of meningitis. The most common is viral meningitis. You get it when a virus enters the body through the nose or mouth and travels to the brain. Bacterial meningitis is rare but can be deadly.

Read the full article at MedlinePlus

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

Convert A87.1 to ICD-9-CMHistory

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

ICD-9-CM
049.1 Adenoviral meningitis
Exact Match The mapping is direct, with no qualifiers.

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 A87.1Overview

Is A87.1 (Viral meningitis) a billable code?

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

What is the ICD-9 equivalent of A87.1?

Under the General Equivalence Mappings, adenoviral meningitis converts to ICD-9-CM 049.1 (adenoviral meningitis). The mapping is a direct match.

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.