2026 ICD-10-CM Diagnosis Code B66.8Other specified fluke infections

ICD-10-CM Codes›A00–B99›B65-B83›B66

ICD-10-CM B66.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B66.8 is a billable ICD-10-CM diagnosis code for other specified fluke infections. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 867 through 869. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
B66.8
Billable Status
Yes — Valid for Submission
Code Describes
Other specified fluke infections
Short Description
Other specified fluke infections
Same as the full description in the CMS dataset.
Parent Code
B66
Other fluke infections

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB65-B83Helminthiases
CategoryB66Other fluke infections
This CodeB66.8Other specified fluke infections

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cutaneous fluke infection
  • Disease caused by Cyclocoelidae
  • Disease caused by Dactylogyridae
  • Disease caused by Dicrocoeliidae
  • Disease caused by Diplostomatidae
  • Disease caused by Echinostomatidae
  • Disease caused by Gastrodiscoides
  • Disease caused by Heterophyidae
  • Disease caused by Notocotylidae
  • Disease caused by Paramphistomatidae
  • Disease caused by Plagiorchiidae
  • Disease caused by Sanguinicolidae
  • Disease caused by Strigeidae
  • Echinostoma ilocanum infection
  • Echinostomiasis
  • Gastrodiscoidiasis
  • Haplorchiasis
  • Infection by Alaria
  • Infection by Amphimerus
  • Infection by Amphimerus elongatus
  • Infection by Apatemon
  • Infection by Apophallus
  • Infection by Athesmia
  • Infection by Athesmia foxi
  • Infection by Austrobilharzia
  • Infection by Bilharziella
  • Infection by Calicophoron
  • Infection by Catatropis
  • Infection by Ceylonocotyle
  • Infection by Collyriculum
  • Infection by Collyriculum faba
  • Infection by Cotylophoron
  • Infection by Cotylurus
  • Infection by Cryptocotyle
  • Infection by Dactylogyrus
  • Infection by Diplostomum
  • Infection by Echinochasmus
  • Infection by Echinoparyphium
  • Infection by Echinostoma lindoense
  • Infection by Euparyphium
  • Infection by Gastrodiscoides hominis
  • Infection by Gigantobilharzia
  • Infection by Gigantocotyle
  • Infection by Heterobilharzia
  • Infection by Heterobilharzia americanum
  • Infection by Heterophyes heterophyes
  • Infection by Hypodereum
  • Infection by Metagonimus yokogawai
  • Infection by Metorchis
  • Infection by Nanophyetus
  • Infection by Nanophyetus salmincola
  • Infection by Notocotylus
  • Infection by Orientobilharzia
  • Infection by Orientobilharzia harinasutai
  • Infection by Ornithobilharzia
  • Infection by pancreaticum
  • Infection by Paramphistomum
  • Infection by Plagiorchis
  • Infection by Platynosomum
  • Infection by Platynosomum concinnum
  • Infection by Platynosomum fastosum
  • Infection by Prosthogonimus
  • Infection by Prosthogonimus macrorchis
  • Infection by Sanguinicola
  • Infection by Schistosomatium
  • Infection by Stellantchasmus falcatus
  • Infection by Strigea
  • Infection by Trichobilharzia
  • Infection by Trichobilharzia ocellata
  • Infection by Trichobilharzia physellae
  • Infection by Trichobilharzia stagnicolae
  • Infection by Typhlocoelum
  • Infection caused by Eurytrema
  • Infection of intestine caused by Fibricola seoulensis
  • Phaneropsuliasis
  • Poikilorchiasis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Echinostomiasis
  • Heterophyiasis
  • Metagonimiasis
  • Nanophyetiasis
  • Watsoniasis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Echinostomiasis
    • Gastrodisciasis, gastrodiscoidiasis
    • Heterophyes, heterophyiasis(small intestine)
    • Infection, infected, infective(opportunistic)
      • Heterophyes (heterophyes)
    • Infection, infected, infective(opportunistic)
      • Metagonimus
    • Infection, infected, infective(opportunistic)
      • Stellantchasmus falcatus
    • Infestation
      • Echinostomum ilocanum
    • Infestation
      • fluke
        • specified type NEC
    • Infestation
      • Gastrodiscoides hominis
    • Infestation
      • Heterophyes (heterophyes)
    • Infestation
      • Metagonimus (yokogawai)
    • Infestation
      • Stellantchasmus falcatus
    • Metagonimiasis
    • Metagonimus infestation(intestine)
    • Nanophyetiasis
    • Watsoniasis

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Echinostomiasis

    infection by flukes of the genus echinostoma.

Patient EducationClinical

Parasitic Diseases

Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert B66.8 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
121.5 Metagonimiasis
Approximate The match is approximate rather than exact.
ICD-9-CM
121.6 Heterophyiasis
Approximate The match is approximate rather than exact.
ICD-9-CM
121.8 Trematode infection NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About B66.8Overview

Is B66.8 (Other fluke infections) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other specified fluke infections on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does B66.8 group to?

When other specified fluke infections is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 868, 869, with relative weights from 0.7297 to 2.0932 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B66.8?

Under the General Equivalence Mappings, other specified fluke infections converts to ICD-9-CM 121.5 (metagonimiasis), 121.6 (heterophyiasis), and 121.8 (trematode infection NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.