2026 ICD-10-CM Diagnosis Code A64Unspecified sexually transmitted disease

ICD-10-CM Codes›A00–B99›A50-A64›A64

ICD-10-CM A64
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A64 is a billable ICD-10-CM diagnosis code for unspecified sexually transmitted disease. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 727 through 728, 742 through 743, 757 through 759. Coders also document this condition as sexually transmitted bacterial disease affecting skin. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sexually transmitted infections (excluding HIV and hepatitis).

Code Identity

ICD-10-CM Code
A64
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified sexually transmitted disease
Chapter
A50-A64
Infections with a predominantly sexual mode of transmission

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA50-A64Infections with a predominantly sexual mode of transmission
CategoryA64Unspecified sexually transmitted disease
This CodeA64Unspecified sexually transmitted disease

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Sexually transmitted bacterial disease affecting skin
  • Sexually transmitted infectious disease
  • Venereal disease in pregnancy

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.

    • Disease, diseased
      • sexually transmitted
    • Disease, diseased
      • venereal
    • Venereal
      • disease

Clinical ClassificationClinical

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

CCSR INF010
Sexually transmitted infections (excluding HIV and hepatitis)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Sexually Transmitted Infections

Sexually transmitted infections (STIs) are infections that are passed from one person to another through sexual contact. If not treated, a STI can develop into a sexually transmitted disease (STD).

The full article covers:

  • What are sexually transmitted infections (STIs)?
  • What causes sexually transmitted infections (STIs)?
  • Who is affected by sexually transmitted infections (STIs)?
  • What are the symptoms of sexually transmitted infections (STIs)?
  • How are sexually transmitted infections (STIs) diagnosed?
  • What are the treatments for sexually transmitted infections (STIs)?
  • Can sexually transmitted infections (STIs) be prevented?

Read the full article at MedlinePlus

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

Convert A64 to ICD-9-CMHistory

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

ICD-9-CM
099.9 Venereal disease 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 A64Overview

Is A64 (Unspecified sexually transmitted disease) a billable code?

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

What MS-DRG does A64 group to?

When unspecified sexually transmitted disease is the principal diagnosis on an inpatient stay, it groups to MS-DRG 727, 728, 742, 743, 757, 758, 759, with relative weights from 0.6636 to 1.8348 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A64?

Under the General Equivalence Mappings, unspecified sexually transmitted disease converts to ICD-9-CM 099.9 (venereal disease 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.