2026 ICD-10-CM Diagnosis Code A59.9Trichomoniasis, unspecified

ICD-10-CM Codes›A00–B99›A50-A64›A59

ICD-10-CM A59.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A59.9 is a billable ICD-10-CM diagnosis code for trichomoniasis, unspecified. 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. Coders also document this condition as asymptomatic trichomoniasis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parasitic, other specified and unspecified infections; and Sexually transmitted infections (excluding HIV and hepatitis).

Code Identity

ICD-10-CM Code
A59.9
Billable Status
Yes — Valid for Submission
Code Describes
Trichomoniasis, unspecified
Short Description
Trichomoniasis, unspecified
Same as the full description in the CMS dataset.
Parent Code
A59
Trichomoniasis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA50-A64Infections with a predominantly sexual mode of transmission
CategoryA59Trichomoniasis
This CodeA59.9Trichomoniasis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Asymptomatic trichomoniasis
  • Disease caused by Trichomonadidae
  • Infection by Trichomonas

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.

    • Infection, infected, infective(opportunistic)
      • Trichomonas
    • Pruritus, pruritic(essential)
      • Trichomonas
    • Trichomoniasis

Clinical ClassificationClinical

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

CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient No · outpatient No
CCSR INF010
Sexually transmitted infections (excluding HIV and hepatitis)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Trichomoniasis

Trichomoniasis is a sexually transmitted infection (STI) caused by a parasite. It spreads from person to person during sex. Many people do not have any symptoms. If you do get symptoms, they usually happen within 5 to 28 days after being infected.

Read the full article at MedlinePlus

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

Convert A59.9 to ICD-9-CMHistory

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

ICD-9-CM
131.9 Trichomoniasis 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 A59.9Overview

Is A59.9 (Trichomoniasis) a billable code?

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

What MS-DRG does A59.9 group to?

When trichomoniasis, unspecified 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 A59.9?

Under the General Equivalence Mappings, trichomoniasis, unspecified converts to ICD-9-CM 131.9 (trichomoniasis 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.