2027 ICD-10-CM Diagnosis Code A56.3Chlamydial infection of anus and rectum
ICD-10-CM Codes›A00–B99›A50-A64›A56
- Billable — Valid for Submission
- Not Chronic
A56.3 is a billable ICD-10-CM diagnosis code for chlamydial infection of anus and rectum. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 393 through 395. Coders also document this condition as Chlamydia trachomatis infection of anus and rectum. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Anal and rectal conditions and Sexually transmitted infections (excluding HIV and hepatitis).
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chlamydia trachomatis infection of anus and rectum
- Chlamydial infection of anus and rectum
- Infection of anus caused by Chlamydia trachomatis
- Infection of rectum caused by Chlamydia trachomatis
- Infection of skin caused by Chlamydia
- Infective proctitis
- Intestinal Chlamydia trachomatis infection
- Proctitis caused by Chlamydia trachomatis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to A56.3: its own notes plus those printed at A56, 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.
- sexually transmitted diseases due to Chlamydia
- trachomatis
- 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.
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.
- human immunodeficiency virus [HIV] disease (B20)
- 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.
- 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 A56.3, its category, or a range that includes it.
Applicable To 1
These notes mention A56.3.
- O98.3 Other infections with a predominantly sexual mode of transmission complicating pregnancy, childbirth and the puerperium
Excludes1 2
These codes carry an Excludes1 note naming A56.3: they are not reported together with it, unless the two conditions are unrelated.
- Block A70-A74 Other diseases caused by chlamydiae
- A74 Other diseases caused by chlamydiae
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Disease, diseased See Also: Syndrome;
chlamydial A56.3
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Anal Disorders
Your anus is the opening at the end of your large intestine. It is where stool (poop) leaves your body.
The full article covers:
- What is the anus?
- What are anal disorders?
- What are the symptoms of anal disorders?
- How are anal disorders diagnosed?
- How are anal disorders treated?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert A56.3 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About A56.3Overview
What is the ICD-10 code for chlamydial infection of anus and rectum?
The ICD-10-CM code for chlamydial infection of anus and rectum is A56.3 (sometimes written as A563). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is A56.3 (Other sexually transmitted chlamydial diseases) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report chlamydial infection of anus and rectum on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does A56.3 group to?
When chlamydial infection of anus and rectum is the principal diagnosis on an inpatient stay, it groups to MS-DRG 394, 395, 393, with relative weights from 0.6379 to 1.5877 depending on complications. Higher weights mean higher Medicare reimbursement.
Can A56.3 be reported with P39.1?
Not as a rule. The Excludes1 note at A56, which applies to A56.3, 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 A56.3?
Under the General Equivalence Mappings, chlamydial infection of anus and rectum converts to ICD-9-CM 099.52 (oth VD chlm trch ans rct). The mapping is a direct match.
