2026 ICD-10-CM Diagnosis Code B94.1Sequelae of viral encephalitis

ICD-10-CM Codes›A00–B99›B90-B94›B94

ICD-10-CM B94.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B94.1 is a billable ICD-10-CM diagnosis code for sequelae of viral encephalitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is exempt from POA reporting. Coders also document this condition as late effects of viral encephalitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sequela of specified infectious disease conditions and Sequela of specified nervous system conditions.

Code Identity

ICD-10-CM Code
B94.1
Billable Status
Yes — Valid for Submission
Code Describes
Sequelae of viral encephalitis
Short Description
Sequelae of viral encephalitis
Same as the full description in the CMS dataset.
Parent Code
B94
Sequelae of other and unspecified infectious and parasitic diseases

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB90-B94Sequelae of infectious and parasitic diseases
CategoryB94Sequelae of other and unspecified infectious and parasitic diseases
This CodeB94.1Sequelae of viral encephalitis

Present on Admission (POA)Billing

B94.1 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Late effects of viral encephalitis

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.

    • Sequelae(of)
      • encephalitis or encephalomyelitis (conditions in G04)
        • viral
    • Sequelae(of)
      • viral
        • encephalitis

Clinical ClassificationClinical

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

CCSR INF011
Sequela of specified infectious disease conditions
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR NVS022
Sequela of specified nervous system conditions
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Encephalitis

Encephalitis is inflammation (swelling) of the brain. It can happen when an infection or medical condition that affects the brain activates your immune system. The inflammation can cause a wide range of symptoms. In extreme cases, it can lead to brain damage, stroke, or even death.

The full article covers:

  • What is encephalitis?
  • What causes encephalitis?
  • Who is more likely to get encephalitis?
  • What are the symptoms of encephalitis?
  • How is encephalitis diagnosed?
  • What are the treatments for encephalitis?
  • Can encephalitis be prevented?

Read the full article at MedlinePlus

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

Convert B94.1 to ICD-9-CMHistory

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

ICD-9-CM
139.0 Late eff viral encephal
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 B94.1Overview

Is B94.1 a billable code?

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

Is B94.1 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for sequelae of viral encephalitis on inpatient claims.

What is the ICD-9 equivalent of B94.1?

Under the General Equivalence Mappings, sequelae of viral encephalitis converts to ICD-9-CM 139.0 (late eff viral encephal). 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.