ICD-10-CM 2027
ICD-10 code for chlamydia
From the official ICD-10-CM alphabetic index entry “Chlamydia, chlamydial”. Page updated September 29, 2026.
About coding chlamydia
The ICD-10-CM code for chlamydia is A74.9 (Chlamydial infection, unspecified). The official index lists 17 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on A74.9.
Within A74, choose A74.9 (Chlamydial infection, unspecified) only when documentation doesn't support a more specific option: chlamydial conjunctivitis (A74.0) and other chlamydial diseases (A74.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 865 (Viral Illness with MCC, relative weight 1.3485) and DRG 866 (Viral Illness without MCC, relative weight 0.8692), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific chlamydia codes (official index)
- cervicitis A56.09 — Other chlamydial infection of lower genitourinary tract
- conjunctivitis A74.0 — Chlamydial conjunctivitis
- cystitis A56.01 — Chlamydial cystitis and urethritis
- endometritis A56.11 — Chlamydial female pelvic inflammatory disease
- epididymitis A56.19 — Other chlamydial genitourinary infection
- female
- pelvic inflammatory disease A56.11 — Chlamydial female pelvic inflammatory disease
- pelviperitonitis A56.11 — Chlamydial female pelvic inflammatory disease
- orchitis A56.19 — Other chlamydial genitourinary infection
- peritonitis A74.81 — Chlamydial peritonitis
- pharyngitis A56.4 — Chlamydial infection of pharynx
- proctitis A56.3 — Chlamydial infection of anus and rectum
- psittaci (infection) A70 — Chlamydia psittaci infections
- salpingitis A56.11 — Chlamydial female pelvic inflammatory disease
- sexually-transmitted infection NEC A56.8 — Sexually transmitted chlamydial infection of other sites
- specified NEC A74.89 — Other chlamydial diseases
- urethritis A56.01 — Chlamydial cystitis and urethritis
- vulvovaginitis A56.02 — Chlamydial vulvovaginitis
Common questions about chlamydia ICD-10 codes
What is the ICD-10 code for chlamydia?
- A74.9 — Chlamydial infection, unspecified. More specific codes apply when the documentation supports them: A56.09, A74.0, A56.01, A56.11 and others below.
What is the ICD-10 code for cervicitis chlamydia?
- A56.09 — Other chlamydial infection of lower genitourinary tract.
What is the ICD-10 code for conjunctivitis chlamydia?
- A74.0 — Chlamydial conjunctivitis.
What is the ICD-10 code for cystitis chlamydia?
- A56.01 — Chlamydial cystitis and urethritis.
What is the ICD-10 code for endometritis chlamydia?
- A56.11 — Chlamydial female pelvic inflammatory disease.
What is the ICD-10 code for epididymitis chlamydia?
- A56.19 — Other chlamydial genitourinary infection.
What is the ICD-10 code for orchitis chlamydia?
- A56.19 — Other chlamydial genitourinary infection.
Is A74.9 billable?
- Yes. A74.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can A74.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict A74.9 as a principal diagnosis.
Is A74.9 a CC or MCC?
- No. A74.9 is neither a CC nor an MCC under MS-DRG v44.0.