ICD-10 Code A85 – Other Viral Encephalitis, Not Elsewhere Classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A85 – Other viral encephalitis, not elsewhere classified
What it is
This code identifies viral encephalitis that is documented but not classified elsewhere. Use it when the record supports inflammation of the brain caused by a virus, and no more specific encephalitis code applies.
Clinical signs
Clinical features vary; refer to documentation. Commonly documented findings include altered mental status, confusion, fever, seizures, headache, or focal neurologic deficits consistent with encephalitis.
When to use this code
Use A85 when the provider documents other viral encephalitis and does not name a specific virus or a more precise diagnosis. It is appropriate when the chart clearly supports viral brain inflammation but the organism is unspecified or not separately classifiable.
Code from the provider’s final diagnosis, not from suspicion alone. If the record identifies a specific viral cause or another encephalitis category, choose the more specific code instead.
Do not use for
Do not use this code for encephalopathy, meningitis, or nonspecific viral illness without encephalitis. Check documentation if the condition is coded elsewhere or if the viral cause is specified.
Coding tip
Look for the exact provider wording “viral encephalitis” and confirm whether a more specific organism code is available before assigning A85.