A86

Unspecified viral encephalitis

Billable FY2026 2025-10-01 → 2026-09-30

Exclusions 8 never code together

A80-A89block

Excludes1

postpolio syndrome (G14)G14
sequelae of poliomyelitis (B91)B91
sequelae of viral encephalitis (B94.1)B94.1

A00-B99chapter

Excludes1

certain localized infections - see body system-related chapters

Excludes2

carrier or suspected carrier of infectious disease (Z22.-)Z22.-
infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)O98.-
infectious and parasitic diseases specific to the perinatal period (P35-P39)P35-P39
influenza and other acute respiratory infections (J00-J22)J00-J22

Excludes1 — never code together. The excluded condition and this one are mutually exclusive.

Excludes2 — not included here, but the patient may have both. Code both when documented.

Instructional notes 4

A86code

Inclusion terms

Viral encephalomyelitis NOS
Viral meningoencephalitis NOS

A00-B99chapter

Includes

diseases generally recognized as communicable or transmissible

Use additional code

code to identify resistance to antimicrobial drugs (Z16.-)Z16.-

Index entries leading here 3

Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) G04.90
- acute A86
- epidemic NEC (viral) A86
- postviral NEC A86
- viral, virus A86
- infectious (acute) (virus) NEC A86
- endemic (viral) A86
Meningoencephalitis G04.90
- acute NEC A86
- infectious (acute) (viral) A86
- virus NEC A86
Meningoencephalomyelitis — see also Meningoencephalitis
- acute NEC (viral) A86

Medications 1

7 Encephalitis, Viral drugs

MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.

Additional references

AHA Coding Clinic® Licence required

Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.

Risk adjustment

Maps to no condition category in any loaded model.

Presence is a property of the code. Untick a model to hide it everywhere.

This code

Billable: yes
Code set: FY2026
Block: A80-A89

Present FY2024–FY2027.