2027 ICD-10-CM Diagnosis Code A74.81Chlamydial peritonitis
ICD-10-CM Codes›A00–B99›A70-A74›A74
- Billable — Valid for Submission
- Not Chronic
A74.81 is a billable ICD-10-CM diagnosis code for chlamydial peritonitis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 865 through 866. Coders also document this condition as chlamydial perihepatitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Peritonitis and intra-abdominal abscess.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chlamydial perihepatitis
- Chlamydial peritonitis
- Fitz-Hugh-Curtis syndrome
- Infection of peritoneum caused by Chlamydia trachomatis
- Inflammation of pelvis caused by Chlamydia trachomatis
- Pelvic peritonitis
- Perihepatitis
- Perihepatitis caused by Chlamydia trachomatis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to A74.81: 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.
- 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.
- 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 A74.81, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming A74.81: they are not reported together with it, unless the two conditions are unrelated.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion) K65.9
chlamydial A74.81
Syndrome See Also: Disease;
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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 A74.81 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About A74.81Overview
What is the ICD-10 code for chlamydial peritonitis?
The ICD-10-CM code for chlamydial peritonitis is A74.81 (sometimes written as A7481). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is A74.81 (Other chlamydial diseases) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report chlamydial peritonitis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does A74.81 group to?
When chlamydial peritonitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 866, 865, with relative weights from 0.8691 to 1.3153 depending on complications. Higher weights mean higher Medicare reimbursement.
Can A74.81 be reported with P39.1?
Not as a rule. The Excludes1 note at A74, which applies to A74.81, 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 A74.81?
Under the General Equivalence Mappings, chlamydial peritonitis converts to ICD-9-CM 079.88 (oth spcf chlamydial infc). The mapping is approximate, so confirm the match fits the documentation.
