B66.3 Fascioliasis

The ICD-10-CM code for Fascioliasis is B66.3 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

1: Certain infectious and parasitic diseases (A00-B99)

Section

B65-B83: Helminthiases (B65-B83)

Category B66

9 codes (8 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to B66.3:

• Fascioliasis
• Distoma hepaticum infestation
• Distomiasis › bile passages
• Flukes NEC › liver
• Infection, infected, infective (opportunistic) › Fasciola (gigantica) (hepatica) (indica)
• Distomiasis › hepatic
• Distomiasis › liver
• Infection, infected, infective (opportunistic) › sheep liver fluke

Inclusion Terms

• Infection due to Fasciola gigantica
• Infection due to Fasciola hepatica
• Infection due to Fasciola indica
• Sheep liver fluke disease

U.S. Hospital Utilization

B66.3 appeared in too few sampled U.S. inpatient stays in 2023 to report a national estimate (AHRQ suppresses counts of 10 or fewer) — a rare inpatient diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

HIV Infections (TOC entry)

a. Human Immunodeficiency Virus (HIV) Infections .............................................................. 19

Infectious agents causing diseases in other chapters (TOC)

b. Infectious agents as the cause of diseases classified to other chapters ................................. 22

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)