2026 ICD-10-CM Diagnosis Code A50.9Congenital syphilis, unspecified

ICD-10-CM Codes›A00–B99›A50-A64›A50

ICD-10-CM A50.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A50.9 is a billable ICD-10-CM diagnosis code for congenital syphilis, 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 congenital syphilis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Perinatal infections and Sexually transmitted infections (excluding HIV and hepatitis).

Code Identity

ICD-10-CM Code
A50.9
Billable Status
Yes — Valid for Submission
Code Describes
Congenital syphilis, unspecified
Short Description
Congenital syphilis, unspecified
Same as the full description in the CMS dataset.
Parent Code
A50
Congenital syphilis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA50-A64Infections with a predominantly sexual mode of transmission
CategoryA50Congenital syphilis
This CodeA50.9Congenital syphilis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Congenital syphilis
  • Gingival disease caused by bacteria
  • Gingival disease caused by Treponema pallidum
  • Hypoplasia of enamel due to congenital syphilis
  • Oral syphilis
  • Pericellular fibrosis of congenital syphilis
  • Syphilis test finding
  • Treponema pallidum detected by enzyme-linked immunosorbent assay

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.

    • Syphilis, syphilitic(acquired)
      • congenital

Clinical ClassificationClinical

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

CCSR PNL009
Perinatal infections
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INF010
Sexually transmitted infections (excluding HIV and hepatitis)
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Congenital Syphilis

    a life-threatening bacterial infection of the newborn caused by treponema pallidum. it is transmitted to the infant from a mother with syphilis through the placenta during pregnancy. signs and symptoms include irritability, fever, failure to thrive, saddle nose, cutaneous rash, and pneumonia.

  • Late Latent Congenital Syphilis

    the occurrence of syphilis symptoms in individuals who were infected before or during birth and have not exhibited signs of the disease for over a year.

Patient EducationClinical

Syphilis

Syphilis is a sexually transmitted infection (STI) caused by bacteria. It infects the genital area, lips, mouth, or anus of both men and women. You usually get syphilis from sexual contact with someone who has it. It can also pass from mother to baby during pregnancy.

Read the full article at MedlinePlus

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

Convert A50.9 to ICD-9-CMHistory

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

ICD-9-CM
090.9 Congenital syphilis 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 A50.9Overview

Is A50.9 (Congenital syphilis) a billable code?

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

What MS-DRG does A50.9 group to?

When congenital syphilis, 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 A50.9?

Under the General Equivalence Mappings, congenital syphilis, unspecified converts to ICD-9-CM 090.9 (congenital syphilis 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.