B00.4 Herpesviral encephalitis
The ICD-10-CM code for Herpesviral encephalitis is B00.4 (FY2026). It is a billable, claim-ready diagnosis code.
Classification
- Section
- B00-B09: Viral infections characterized by skin and mucous membrane lesions (B00-B09)
- Category B00
- 18 codes (15 billable)
- FY2026 Status
- Stable since FY2024
Also Known As
ICD-10-CM Alphabetic Index entries that lead to B00.4:
- Disease, diseased › simian B
- Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › herpesviral
- Herpes, herpesvirus, herpetic › encephalitis
- Meningoencephalitis › herpesviral, herpetic
- Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › in (due to) › herpes (simplex) virus
- Meningoencephalitis › in (due to) › herpes
Inclusion Terms
- Herpesviral meningoencephalitis
- Simian B disease
U.S. Hospital Utilization
- An estimated 3,360 U.S. inpatient stays in 2023 included B00.4 among the documented diagnoses.
- 1,455 stays listed it as the principal diagnosis.
Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.
Official Coding Guidelines
HIV Infections (TOC entry)a. Human Immunodeficiency Virus (HIV) Infections .............................................................. 19
Infectious agents causing diseases in other chapters (TOC)b. Infectious agents as the cause of diseases classified to other chapters ................................. 22
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026