ICD-10 Code B66.1 – Clonorchiasis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B66.1 – Clonorchiasis
What it is
B66.1 identifies clonorchiasis, a parasitic infection caused by Clonorchis sinensis. Use it when documentation confirms infection with this liver fluke, usually acquired from eating contaminated freshwater fish.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include abdominal discomfort, jaundice, and biliary tract involvement, but many patients may have few or no symptoms.
When to use this code
Use B66.1 when the record clearly documents clonorchiasis or Clonorchis sinensis infection. Apply it for confirmed active infection, whether identified by clinician assessment, imaging-supported biliary disease, or other documented diagnostic evidence. Check documentation if the parasite is only suspected.
Do not use for
Do not use this code for nonspecific intestinal parasitic infections or for exposure without confirmed disease. If the chart only mentions possible infestation or another liver fluke, check documentation.
Coding tip
Code the specific parasite named in the record; if clonorchiasis is not explicitly documented, verify the diagnosis before assigning B66.1.