2027 ICD-10-CM Diagnosis Code A74.0Chlamydial conjunctivitis

ICD-10-CM Codes›A00–B99›A70-A74›A74

ICD-10-CM A74.0
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

A74.0 is a billable ICD-10-CM diagnosis code for chlamydial conjunctivitis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 124 through 125. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Cornea and external disease.

Code Identity

ICD-10-CM Code
A74.0
Billable Status
Yes — Valid for Submission
Code Describes
Chlamydial conjunctivitis
Short Description
Chlamydial conjunctivitis
Same as the full description in the CMS dataset.
Parent Code
Other diseases caused by chlamydiae

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA70-A74Other diseases caused by chlamydiae
CategoryA74Other diseases caused by chlamydiae
This CodeA74.0Chlamydial conjunctivitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral chlamydial conjunctivitis
  • Chlamydial conjunctivitis
  • Chronic chlamydial follicular conjunctivitis
  • Chronic follicular conjunctivitis
  • Conjunctivitis of bilateral eyes caused by bacteria
  • Conjunctivitis of left eye caused by Chlamydia trachomatis
  • Conjunctivitis of right eye caused by Chlamydia trachomatis
  • Inclusion conjunctivitis of the adult
  • Neonatal bacterial dacryocystitis
  • Neonatal chlamydial dacryocystitis
  • Neonatal chlamydial infection
  • Neonatal dacryocystitis
  • Trachoma

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to A74.0: its own notes plus those printed at A74, block A70-A74, 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.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Paratrachoma

Excludes1

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

From A74 Other diseases caused by chlamydiae applies to 4 codes
  • neonatal chlamydial conjunctivitis (P39.1)
  • neonatal chlamydial pneumonia (P23.1)
  • Reiter's disease (M02.3-)
  • sexually transmitted chlamydial diseases (A55-A56)
From Block A70-A74 Other diseases caused by chlamydiae applies to 8 codes
  • sexually transmitted chlamydial diseases (A55-A56)

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.

From A74 Other diseases caused by chlamydiae applies to 4 codes
  • chlamydial pneumonia (J16.0)
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 A74.0, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming A74.0: its condition is not part of those codes, and both may be reported when the patient has both.

  • A56 Other sexually transmitted chlamydial diseases
    conditions classified to A74.- names A74.-, which includes this code

Index to Diseases and InjuriesGuidance

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR EYE001
Cornea and external disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Bacterial Infections

Bacteria are tiny organisms (living things) that have only one cell. Under a microscope, they look like balls, rods, or spirals. They can be found almost everywhere on Earth. There are lots of bacteria in and on your body. In fact, your body has about 10 times more bacteria cells than human cells.

The full article covers:

  • What are bacteria?
  • How do bacterial infections spread?
  • What are the treatments for bacterial infections?
  • Can bacterial infections be prevented?

Read the full article at MedlinePlus

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

Convert A74.0 to ICD-9-CMHistory

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

ICD-9-CM
077.0 Inclusion conjunctivitis
Approximate The match is approximate rather than exact.
ICD-9-CM
077.98 Unsp ds conjuc chlamydia
Approximate The match is approximate rather than exact.

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 A74.0Overview

What is the ICD-10 code for chlamydial conjunctivitis?

The ICD-10-CM code for chlamydial conjunctivitis is A74.0 (sometimes written as A740). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is A74.0 (Other diseases caused by chlamydiae) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report chlamydial conjunctivitis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does A74.0 group to?

When chlamydial conjunctivitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 125, 124, with relative weights from 0.7699 to 1.2470 depending on complications. Higher weights mean higher Medicare reimbursement.

Can A74.0 be reported with P39.1?

Not as a rule. The Excludes1 note at A74, which applies to A74.0, 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).

What is the ICD-9 equivalent of A74.0?

Under the General Equivalence Mappings, chlamydial conjunctivitis converts to ICD-9-CM 077.0 (inclusion conjunctivitis) and 077.98 (unsp ds conjuc chlamydia). The mapping is approximate, so confirm the match fits the documentation.