ICD-10 Code B66.0 – Opisthorchiasis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B66.0 – Opisthorchiasis
What it is
Opisthorchiasis is an infection caused by liver flukes of the Opisthorchis species. Use this code for documented parasitic infection involving the biliary tree or liver.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include abdominal pain, dyspepsia, jaundice, or evidence of biliary inflammation, but confirmation depends on the recorded diagnosis.
When to use this code
Use B66.0 when the provider documents opisthorchiasis, whether acute or chronic, and the infection is the reason for the encounter. It also fits when notes describe confirmed Opisthorchis infestation affecting the hepatobiliary system. If the record only mentions exposure or suspected infection, check documentation before coding.
Do not use for
Do not use this code for nonspecific abdominal symptoms, abnormal liver tests, or general helminth infections without named opisthorchiasis. If another parasite is identified, code that specific condition instead.
Coding tip
Code the documented organism and site carefully; if the note lacks confirmation, query or check documentation.