ICD-10 Code B64 – Unspecified Protozoal Disease (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B64 – Unspecified protozoal disease
What it is
This code identifies a protozoal infection when the organism is known to be a protozoan but the specific disease is not named in the record. Use it for nonspecific documentation only.
Clinical signs
Clinical features vary; refer to documentation. Protozoal infections may present with gastrointestinal, systemic, or other organ-specific findings depending on the organism and site involved.
When to use this code
Use B64 when the provider documents a protozoal disease but does not specify the exact protozoan infection. It also fits when the note confirms protozoal etiology without a more precise diagnosis. If the organism or disease is identified elsewhere in the chart, code the more specific entry instead.
Do not use for
Do not use this code for bacterial, viral, fungal, or helminth infections. Also avoid it when documentation supports a specific protozoal diagnosis or when the record only says “infection” without protozoal confirmation.
Coding tip
Check documentation for the exact protozoal diagnosis before defaulting to B64.