ICD10BillableValid for clinical use
ICD-10 Code A85.1: Adenoviral encephalitis
Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026
What is this code?
ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Certain infectious and parasitic diseases (A00-B99).
When is it used?
- May be used when a clinician documents adenoviral encephalitis in a patient's medical record.
- May appear in hospital records, claims, referrals, and clinical documentation.
- This code can be used as a clinically usable diagnosis entry in standardized coding workflows.
What it does not mean
- A code alone does not explain severity, treatment plan, or outcome.
- A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
Code hierarchy
chapter
1Certain infectious and parasitic diseases (A00-B99)
block
A80-A89Viral and prion infections of the central nervous system
category
A85Other viral encephalitis, not elsewhere classified
currentA85
Official coding notes
Inclusion terms
- Adenoviral meningoencephalitis
Where you may see this code
You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.
Related specialists
Infectious Disease SpecialistGeneral Physician
Related codes
Sibling codes
Coverage-related procedures and services
CPT 87483high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA); CENTRAL NERVOUS SYSTEM PATHOGEN (EG, NEISSERIA MENINGITIDIS, STREPTOCOCCUS PNEUMONIAE, LISTERIA, HAEMOPHILUS INFLUENZAE, E. COLI, STREPTOCOCCUS AGALACTIAE, ENTEROVIRUS, HUMAN PARECHOVIRUS, HERPES SIMPLEX VIRUS TYPE 1 AND 2, HUMAN HERPESVIRUS 6, CYTOMEGALOVIRUS, VARICELLA ZOSTER VIRUS, CRYPTOCOCCUS), INCLUDES MULTIPLEX REVERSE TRANSCRIPTION, WHEN PERFORMED, AND MULTIPLEX AMPLIFIED PROBE TECHNIQUE, MULTIPLE TYPES OR SUBTYPES, 12-25 TARGETS
Source: CMS coverage guidance
CPT 70460high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITH CONTRAST MATERIAL(S)
Source: CMS coverage guidance
CPT 70450high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITHOUT CONTRAST MATERIAL
Source: CMS coverage guidance
CPT 70470high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITHOUT CONTRAST MATERIAL, FOLLOWED BY CONTRAST MATERIAL(S) AND FURTHER SECTIONS
Source: CMS coverage guidance
CPT 72126high
COMPUTED TOMOGRAPHY, CERVICAL SPINE; WITH CONTRAST MATERIAL
Source: CMS coverage guidance
CPT 72125high
COMPUTED TOMOGRAPHY, CERVICAL SPINE; WITHOUT CONTRAST MATERIAL
Source: CMS coverage guidance
Mapped diagnoses and classifications
SNOMED_CT 35640008high
Acute adenoviral encephalitis
Source: SNOMED International ICD-10 map
SNOMED_CT 82547005high
Acute adenoviral meningoencephalitis
Source: SNOMED International ICD-10 map
SNOMED_CT 56529007high
Adenoviral encephalitis
Source: SNOMED International ICD-10 map
SNOMED_CT 111851005high
Subacute adenoviral encephalitis
Source: SNOMED International ICD-10 map
SNOMED_CT 713260006high
Subacute adenoviral encephalitis co-occurrent with human immunodeficiency virus infection
Source: SNOMED International ICD-10 map
SNOMED_CT 421415007high
Subacute adenoviral encephalitis with AIDS (acquired immunodeficiency syndrome)
Source: SNOMED International ICD-10 map
Coding guidelines
Compatibility
Legacy and official ICD code match exactly.
Legacy codes
A85.1
Common synonyms
Adenoviral encephalitis
Frequently asked questions
About this content
This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.