A84.9 Tick-borne viral encephalitis, unspecified

Billable ICD-10-CM code, FY2026. Acts as a Major Complication or Comorbidity (MCC) as a secondary diagnosis.

Applies from A84 Tick-borne viral encephalitis

Includes

• tick-borne viral meningoencephalitis

MS-DRG index

Defines the logic of DRG(s) 023-024 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 063.9 Tick-borne viral encephalitis, unspecified

Diagnosis Index entries for A84.9

• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › tick-borne
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › viral, virus › arthropod-borne NEC › tick-borne
• Infection, infected, infective (opportunistic) › virus, viral NOS › encephalitis, tick-borne

Nearby codes

• 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
• A84.81 Powassan virus disease
• A84.89 Other tick-borne viral encephalitis
• A84.9 Tick-borne viral encephalitis, unspecified (this code)