ICD-10 Code B33.3 – Retrovirus infections, not elsewhere classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B33.3 – Retrovirus infections, not elsewhere classified
What it is
B33.3 identifies a retrovirus infection that does not fit a more specific ICD-10 category. Use it when documentation confirms a retroviral infection, but the record does not name a more precise diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Retroviral infections may be associated with systemic illness, immune dysfunction, or other organ involvement, depending on the specific virus and stage of disease.
When to use this code
Use B33.3 when the provider documents a retrovirus infection and no more specific code is available or supported. It is appropriate when the chart names a retroviral infection without identifying a distinct subtype. If the record is unclear, check documentation before assigning the code.
Do not use for
Do not use this code for a clearly identified retroviral disease that has its own ICD-10 code. Also avoid it when the record only suggests exposure, screening, or suspected infection without a confirmed diagnosis.
Coding tip
Code the most specific retroviral diagnosis documented, and use B33.3 only when the record supports a nonspecific retrovirus infection.