U.S. ICD-10-CM · FY 2027

A86 ICD-10-CM Code: Unspecified viral encephalitis

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Code definition

Official description

A86

Unspecified viral encephalitis

ICD-10-CM diagnosis code · United States clinical modification

Classification

Where A86 sits

  1. 1

    Chapter 1

    Certain infectious and parasitic diseases (A00-B99)

  2. 2

    Section

    Viral and prion infections of the central nervous system (A80-A89)

  3. 3

    Category A86

    Unspecified viral encephalitis

  4. 4

    Code A86

    Unspecified viral encephalitis

Documentation details

Notes for this code

Inclusion terms

  • Viral encephalomyelitis NOS
  • Viral meningoencephalitis NOS

Code first

No “code first” instruction is listed for A86.

Use additional code

No “use additional code” instruction is listed for A86.

Excludes1

Conditions that should not be reported together with this code.

No Excludes1 note is listed for A86.

Excludes2

Conditions not included here that may be reported separately when present.

No Excludes2 note is listed for A86.

Transparency

Source and release

Data release

U.S. ICD-10-CM · FY 2027

Effective date

Oct 1, 2026

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Code-specific guidance

Frequently asked questions

What does ICD-10-CM code A86 mean?

A86 is the FY 2027 U.S. ICD-10-CM code for “Unspecified viral encephalitis.”

Is A86 a billable or specific ICD-10-CM code?

Yes. In the FY 2027 reference data used on this page, A86 has no child codes and is presented as a billable/specific code. Always confirm the active code set and payer requirements before use.

Where is A86 located in ICD-10-CM?

A86 is listed in Chapter 1, Certain infectious and parasitic diseases (A00-B99), within Viral and prion infections of the central nervous system (A80-A89) (A80–A89), under category A86, Unspecified viral encephalitis.

What coding notes are listed for A86?

Its listed inclusion terms are Viral encephalomyelitis NOS; Viral meningoencephalitis NOS. No code-first instruction is listed. No Excludes1 note is listed. No Excludes2 note is listed.

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