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A86 ICD-10-CA code: Unspecified viral encephalitis

A86 is the ICD-10-CA code for “Unspecified viral encephalitis” in CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026.

Official description

A86

Unspecified viral encephalitis

ICD-10-CA · Canada

Index terms

Entries in CIHI’s alphabetical index that lead to A86. Searching the index by the condition the note names is how coders reach this code.

  • Meningoencephalitis, acute NEC
  • Meningoencephalitis, virus NEC
  • Meningoencephalomyelitis, acute NEC (viral)
  • Meningoencephalitis, infectious (acute) (viral)
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), acute
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), viral, virus
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), postviral NEC
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), endemic (viral)
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), epidemic NEC (viral)
  • Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute), infectious (acute), viral NEC

Notes for A86

As CIHI prints them, with any note A86 takes from the headings above it.

Includes

  • Viral:• encephalomyelitis NOS• meningoencephalitis NOS
  • Diseases generally recognized as communicable or transmissibleFrom Chapter 1: Certain infectious and parasitic diseases (A00-B99)

Use additional code

Add a code for this detail when the note documents it.

  • Use additional code (U82-U84) to identify resistance to antimicrobial drugsFrom Chapter 1: Certain infectious and parasitic diseases (A00-B99)

Excludes

Conditions classified elsewhere.

  • Sequelae of:• poliomyelitis (B91)• viral encephalitis (B94.1)From A80-A89 Viral infections of the central nervous system
  • Carrier or suspected carrier of infectious disease (Z22.-)certain localized infections - see body system-related chaptersinfectious and parasitic diseases:• complicating pregnancy, childbirth and the puerperium [except obstetrical tetanus] (O98.-)• specific to the perinatal period [except tetanus neonatorum, whooping cough, congenital syphilis, perinatal gonococcal infection and perinatal human immunodeficiency virus [HIV] disease] (P35-P39)influenza and other acute respiratory infections (J00-J22)From Chapter 1: Certain infectious and parasitic diseases (A00-B99)

Where A86 sits

  1. 1ChapterChapter 1: Certain infectious and parasitic diseases (A00-B99)
  2. 2Block A80-A89Viral infections of the central nervous system
  3. 3Valid code A86Unspecified viral encephalitis

Source and release

Data release
ICD-10-CA · FY 2026–2027
Effective date
Apr 1, 2026
Publisher
CIHI

This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.

See A86 in the CIHI source

Frequently asked questions

What does ICD-10-CA code A86 mean?

A86 is the ICD-10-CA code for “Unspecified viral encephalitis” in CIHI’s ICD-10-CA FY 2026–2027 release.

Where is A86 in ICD-10-CA?

A86 sits under A80-A89 Viral infections of the central nervous system, within Chapter 1: Certain infectious and parasitic diseases (A00-B99).

What coding notes apply to A86?

ICD-10-CA lists Includes, Excludes, Use additional code notes for A86, including those from the headings it sits under. They are listed on this page with where each one comes from.

Which ICD-10-CA release does this page use?

It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.

Codes beside A86

A80Acute poliomyelitisA81Atypical virus infections of central nervous systemA82RabiesA83Mosquito-borne viral encephalitisA84Tick-borne viral encephalitisA85Other viral encephalitis, not elsewhere classifiedA87Viral meningitisA88Other viral infections of central nervous system, not elsewhere classifiedA89Unspecified viral infection of central nervous system