2020 ICD-10-CM Diagnosis Code A86

Unspecified viral encephalitis

    2016 2017 2018 2019 2020 Billable/Specific Code
  • A86 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2020 edition of ICD-10-CM A86 became effective on October 1, 2019.
  • This is the American ICD-10-CM version of A86 - other international versions of ICD-10 A86 may differ.
Applicable To
  • Viral encephalomyelitis NOS
  • Viral meningoencephalitis NOS
The following code(s) above A86 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to A86:
  • A00-B99
    2020 ICD-10-CM Range A00-B99

    Certain infectious and parasitic diseases

    Includes
    • diseases generally recognized as communicable or transmissible
    Type 1 Excludes
    • certain localized infections - see body system-related chapters
    Type 2 Excludes
    • carrier or suspected carrier of infectious disease (Z22.-)
    • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
    • infectious and parasitic diseases specific to the perinatal period (P35-P39)
    • influenza and other acute respiratory infections (J00-J22)
    Use Additional
    • code to identify resistance to antimicrobial drugs (Z16.-)
    Certain infectious and parasitic diseases
  • A80-A89
    2020 ICD-10-CM Range A80-A89

    Viral and prion infections of the central nervous system

    Type 1 Excludes
    • postpolio syndrome (G14)
    • sequelae of poliomyelitis (B91)
    • sequelae of viral encephalitis (B94.1)
    Viral and prion infections of the central nervous system
Approximate Synonyms
  • Encephalitis infective
  • Infective encephalitis
  • Viral encephalitis
Clinical Information
  • Inflammation of brain parenchymal tissue as a result of viral infection. Encephalitis may occur as primary or secondary manifestation of togaviridae infections; herpesviridae infections; adenoviridae infections; flaviviridae infections; bunyaviridae infections; picornaviridae infections; paramyxoviridae infections; orthomyxoviridae infections; retroviridae infections; and arenaviridae infections.
ICD-10-CM A86 is grouped within Diagnostic Related Group(s) (MS-DRG v37.0):
  • 097 Non-bacterial infection of nervous system except viral meningitis with mcc
  • 098 Non-bacterial infection of nervous system except viral meningitis with cc
  • 099 Non-bacterial infection of nervous system except viral meningitis without cc/mcc
  • 974 Hiv with major related condition with mcc
  • 975 Hiv with major related condition with cc
  • 976 Hiv with major related condition without cc/mcc

Convert A86 to ICD-9-CM

Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
Code annotations containing back-references to A86:
  • Type 1 Excludes: A88
    ICD-10-CM Diagnosis Code A88

    Other viral infections of central nervous system, not elsewhere classified

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • viral encephalitis NOS (A86)
    • viral meningitis NOS (A87.9)

Diagnosis Index entries containing back-references to A86:

ICD-10-CM Codes Adjacent To A86
A84 Tick-borne viral encephalitis
A84.0 Far Eastern tick-borne encephalitis [Russian spring-summer encephalitis]
A84.1 Central European tick-borne encephalitis
A84.8 Other tick-borne viral encephalitis
A84.9 Tick-borne viral encephalitis, unspecified
A85 Other viral encephalitis, not elsewhere classified
A85.0 Enteroviral encephalitis
A85.1 Adenoviral encephalitis
A85.2 Arthropod-borne viral encephalitis, unspecified
A85.8 Other specified viral encephalitis
A86 Unspecified viral encephalitis
A87 Viral meningitis
A87.0 Enteroviral meningitis
A87.1 Adenoviral meningitis
A87.2 Lymphocytic choriomeningitis
A87.8 Other viral meningitis
A87.9 Viral meningitis, unspecified
A88 Other viral infections of central nervous system, not elsewhere classified
A88.0 Enteroviral exanthematous fever [Boston exanthem]
A88.1 Epidemic vertigo
A88.8 Other specified viral infections of central nervous system

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.