ICD-10 Code B34 – Viral infection of unspecified site (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B34 – Viral infection of unspecified site
What it is
B34 identifies a viral infection when the affected site is not specified in the record. Use it for a confirmed or presumed viral illness without enough detail for a more exact code.
Clinical signs
Clinical features vary; refer to documentation. Commonly, records may mention nonspecific viral symptoms such as fever, malaise, or upper respiratory complaints, but the site and exact virus are not identified.
When to use this code
Use B34 when the provider documents a viral infection but does not name the anatomic site or a more specific diagnosis. It is also appropriate when the chart supports a viral illness, yet coding cannot be narrowed further. If documentation later identifies the site or organism, choose the more specific code.
Do not use for
Do not use this code when the infection site is known, such as respiratory, gastrointestinal, or skin involvement. Do not use it if documentation supports a more specific viral diagnosis; check documentation.
Coding tip
Before assigning B34, look for a documented site, organism, or more specific viral condition that would replace this unspecified code.