ICD-10 Code B66.9 – Fluke infection, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B66.9 – Fluke infection, unspecified
What it is
B66.9 identifies a fluke infection when the specific species or site is not documented. It is used for parasitic trematode infections that are confirmed or strongly suspected, but not further specified.
Clinical signs
Clinical features vary; refer to documentation. Fluke infections may present with gastrointestinal, hepatobiliary, or other organ-related symptoms depending on the parasite involved.
When to use this code
Use B66.9 when the record states fluke infection, trematode infection, or a similar diagnosis without naming the organism. It also fits when the provider confirms infection but does not document the exact fluke species or anatomic site. Check documentation if the chart suggests a more specific parasitic diagnosis.
Do not use for
Do not use this code when the fluke species is identified and a more specific code is available. Do not assign it for non-parasitic liver, intestinal, or biliary disorders.
Coding tip
Review the provider note for the exact parasite name and site before defaulting to B66.9.