2027 ICD-10-CM Diagnosis Code A56Other sexually transmitted chlamydial diseases

ICD-10-CM Codes›A00–B99›A50-A64›A56

ICD-10-CM A56
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

A56 is a non-billable ICD-10-CM category code for other sexually transmitted chlamydial diseases, so it cannot be submitted on claims. Use a more specific code from this category instead, such as A56.00, A56.01, A56.02, and A56.09.

Code Identity

ICD-10-CM Code
A56
Billable Status
No — Non-Billable Category
Code Describes
Other sexually transmitted chlamydial diseases
Short Description
Other sexually transmitted chlamydial diseases
Same as the full description in the CMS dataset.
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
CategoryA56Other sexually transmitted chlamydial diseases
This CodeA56Other sexually transmitted chlamydial diseases

Specific Coding for Other sexually transmitted chlamydial diseasesOverview

Non-specific codes like A56 require more characters. Use one of these billable codes instead:

  • A56.0 for Chlamydial infection of lower genitourinary tract

  • Use A56.00 for Chlamydial infection of lower genitourinary tract, unspecified

  • Use A56.01 for Chlamydial cystitis and urethritis

  • Use A56.02 for Chlamydial vulvovaginitis

  • Use A56.09 for Other chlamydial infection of lower genitourinary tract

  • A56.1 for Chlamydial infection of pelviperitoneum and other genitourinary organs

  • Use A56.11 for Chlamydial female pelvic inflammatory disease

  • Use A56.19 for Other chlamydial genitourinary infection

  • Use A56.2 for Chlamydial infection of genitourinary tract, unspecified

  • Use A56.3 for Chlamydial infection of anus and rectum

  • Use A56.4 for Chlamydial infection of pharynx

  • Use A56.8 for Sexually transmitted chlamydial infection of other sites

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to A56: its own notes plus those printed at block A50-A64 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

On A56 itself
  • sexually transmitted diseases due to Chlamydia
  • trachomatis
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

On A56 itself
  • neonatal chlamydial conjunctivitis (P39.1)
  • neonatal chlamydial pneumonia (P23.1)
From Block A50-A64 Infections with a predominantly sexual mode of transmission applies to 142 codes
  • nonspecific and nongonococcal urethritis (N34.1)
  • Reiter's disease (M02.3-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

On A56 itself
  • chlamydial lymphogranuloma (A55)
  • conditions classified to A74.-
From Block A50-A64 Infections with a predominantly sexual mode of transmission applies to 142 codes
  • human immunodeficiency virus [HIV] disease (B20)
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name A56, its category, or a range that includes it.

Applicable To 1

These notes mention A56.

  • O98.3 Other infections with a predominantly sexual mode of transmission complicating pregnancy, childbirth and the puerperium
    Conditions in A55-A64 names A55-A64, which includes this code

Excludes1 2

These codes carry an Excludes1 note naming A56: they are not reported together with it, unless the two conditions are unrelated.

  • Block A70-A74 Other diseases caused by chlamydiae
    sexually transmitted chlamydial diseases (A55-A56) names A55-A56, which includes this code
  • A74 Other diseases caused by chlamydiae
    sexually transmitted chlamydial diseases (A55-A56) names A55-A56, which includes this code

Patient EducationClinical

Chlamydia Infections

Chlamydia is a common sexually transmitted infection (STI). It is caused by bacteria called Chlamydia trachomatis. Anyone can get chlamydia. It often doesn't cause symptoms, so people may not know that they have it. Antibiotics can cure it. But if it's not treated, chlamydia can cause serious health problems.

The full article covers:

  • What is chlamydia?
  • How is chlamydia spread?
  • Who is more likely to get chlamydia?
  • What are the symptoms of chlamydia?
  • How is chlamydia diagnosed?
  • Who should be tested for chlamydia?
  • What other problems can chlamydia cause?
  • What are the treatments for chlamydia?

Read the full article at MedlinePlus

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

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About A56Overview

What is the ICD-10 code for other sexually transmitted chlamydial diseases?

A56 is the ICD-10-CM category for other sexually transmitted chlamydial diseases, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is A56 (Other sexually transmitted chlamydial diseases) a billable code?

No. This is a category header that groups the codes for other sexually transmitted chlamydial diseases, and headers cannot be submitted on claims. Claims for other sexually transmitted chlamydial diseases need a more specific code from this category, such as A56.00, A56.01, and A56.02.

Can A56 be reported with P39.1?

Not as a rule. The Excludes1 note on A56 lists "neonatal chlamydial conjunctivitis (P39.1)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).