2026 ICD-10-CM Diagnosis Code A07.9Protozoal intestinal disease, unspecified

ICD-10-CM Codes›A00–B99›A00-A09›A07

ICD-10-CM A07.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A07.9 is a billable ICD-10-CM diagnosis code for protozoal intestinal disease, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 371 through 373. Coders also document this condition as colitis caused by protozoan. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Intestinal infection; and Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
A07.9
Billable Status
Yes — Valid for Submission
Code Describes
Protozoal intestinal disease, unspecified
Short Description
Protozoal intestinal disease, unspecified
Same as the full description in the CMS dataset.
Parent Code
A07
Other protozoal intestinal diseases

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA00-A09Intestinal infectious diseases
CategoryA07Other protozoal intestinal diseases
This CodeA07.9Protozoal intestinal disease, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Colitis caused by protozoan
  • Disease caused by ciliate protozoa
  • Intestinal ciliate infection
  • Intestinal flagellate infection
  • Parasitic infection causing colitis
  • Parasitic infection causing inflammation of small intestine
  • Protozoal enteritis of intestine
  • Protozoal enteritis of small intestine
  • Protozoal intestinal disease

Tabular List NotesGuidance

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

Inclusion Terms

  • Flagellate diarrhea
  • Protozoal colitis
  • Protozoal diarrhea
  • Protozoal dysentery

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.

    • Colitis(acute) (catarrhal) (chronic) (noninfective) (hemorrhagic)
      • protozoal
    • Diarrhea, diarrheal(disease) (infantile) (inflammatory)
      • flagellate
    • Diarrhea, diarrheal(disease) (infantile) (inflammatory)
      • protozoal
    • Disease, diseased
      • intestine
        • protozoal
    • Disease, diseased
      • protozoal
        • intestine, intestinal
    • Dysentery, dysenteric(catarrhal) (diarrhea) (epidemic) (hemorrhagic) (infectious) (sporadic) (tropical)
      • protozoal
    • Enteritis(acute) (diarrheal) (hemorrhagic) (noninfective)
      • protozoal
    • Infection, infected, infective(opportunistic)
      • flagellate, intestinal
    • Infection, infected, infective(opportunistic)
      • protozoal NEC
        • intestinal
    • Infestation
      • protozoal NEC
        • intestinal

Clinical ClassificationClinical

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

CCSR DIG001
Intestinal infection
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Gastroenteritis

Gastroenteritis is an inflammation of the lining of the stomach and intestines. The main symptoms include vomiting and diarrhea. It is usually not serious in healthy people, but it can sometimes lead to dehydration or cause severe symptoms.

The full article covers:

  • What is gastroenteritis?
  • What causes gastroenteritis?
  • What are the symptoms of gastroenteritis?
  • How is gastroenteritis diagnosed?
  • What are the treatments for gastroenteritis?
  • Can gastroenteritis be prevented?

Read the full article at MedlinePlus

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

Convert A07.9 to ICD-9-CMHistory

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

ICD-9-CM
007.9 Protozoal intest dis NOS
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 A07.9Overview

Is A07.9 (Other protozoal intestinal diseases) a billable code?

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

What MS-DRG does A07.9 group to?

When protozoal intestinal disease, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 371, 372, 373, with relative weights from 0.7274 to 1.7731 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A07.9?

Under the General Equivalence Mappings, protozoal intestinal disease, unspecified converts to ICD-9-CM 007.9 (protozoal intest dis NOS). 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.