2026 ICD-10-CM Diagnosis Code B81.0Anisakiasis

ICD-10-CM Codes›A00–B99›B65-B83›B81

ICD-10-CM B81.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B81.0 is a billable ICD-10-CM diagnosis code for anisakiasis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 391 through 392. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
B81.0
Billable Status
Yes — Valid for Submission
Code Describes
Anisakiasis
Short Description
Anisakiasis
Same as the full description in the CMS dataset.
Parent Code
B81
Other intestinal helminthiases, not elsewhere classified

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB65-B83Helminthiases
CategoryB81Other intestinal helminthiases, not elsewhere classified
This CodeB81.0Anisakiasis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Anisakiasis caused by larva of Anisakis simplex
  • Disease caused by Heterocheiloidea
  • Infection by Anisakidae
  • Infection by Anisakis larva
  • Infection by Contracaecum
  • Infection by Cucullanus
  • Infection by Porrocaecum
  • Infection by Pseudoterranova
  • Infection of intestine caused by Anisakis larva
  • Infection of stomach caused by Anisakis marina
  • Parasitic infection causing inflammation of small intestine
  • Parasitic infection of duodenum caused by Anisakis

Tabular List NotesGuidance

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

Inclusion Terms

  • Infection due to Anisakis larva

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.

    • Anisakiasis(infection) (infestation)
    • Anisakis larvae infestation
    • Infection, infected, infective(opportunistic)
      • Anisakiasis, Anisakis larvae
    • Infestation
      • Anisakis larvae, anisakiasis
    • Infestation
      • helminth
        • intestinal
          • anisakiasis

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

  • Anisakiasis

    infection with roundworms of the genus anisakis. human infection results from the consumption of fish harboring roundworm larvae. the worms may cause acute nausea; vomiting; or penetrate into the wall of the digestive tract where they give rise to eosinophilic granuloma in the stomach; intestines; or the omentum.

  • Anisakiasis

    an infection that is caused by nematodes of the genus anisakis, which is most commonly transmitted via ingestion of infective larvae from consumption of raw or undercooked fish or squid; it is characterized by invasion of the stomach wall or intestines, resulting in the death of the worm, and triggering an inflammatory response that surrounds the worm and that can result in intestinal obstruction.

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 B81.0 to ICD-9-CMHistory

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

ICD-9-CM
127.1 Anisakiasis
Exact Match The mapping is direct, with no qualifiers.

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 B81.0Overview

Is B81.0 (Other intestinal helminthiases, not elsewhere classified) a billable code?

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

What MS-DRG does B81.0 group to?

When anisakiasis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 391, 392, with relative weights from 0.7796 to 1.2683 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B81.0?

Under the General Equivalence Mappings, anisakiasis converts to ICD-9-CM 127.1 (anisakiasis). The mapping is a direct match.

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.