Chlamydia trachomatis

Clinical definition of the Chlamydia trachomatis test
Chlamydia infection is a common sexually transmitted infection (STI) in humans caused by the bacterium Chlamydia trachomatis. Chlamydia is a major infectious cause of human genital and eye disease. It can be transmitted during vaginal, anal or oral sex with an infected partner, and can be passed from an infected mother to her baby during vaginal childbirth. These babies are in danger of developing conjunctivitis and pneumonia.

Why is the Chlamydia trachomatis test done?
This test is mainly done to prevent, screen and control Chlamydial infection (an STD) caused by the bacterium Chlamydia trachomatis through early detection. It may be done to treat asymptomatic infection and to reduce the onward transmission of the infection to sexual partners. People at a high risk to contract the infection include those having new or multiple sex partners, those having history of previous infection with another STD or who fail to use condoms consistently.

What are the common signs/symptoms when the Chlamydia trachomatis test is done?

  • Painful or frequent urination
  • Rectal itching
  • Red, swollen, itchy eyes
  • Trachoma
  • For women:-
    • Bleeding between menstrual periods and after sexual intercourse,
    • Abdominal pain
    • Painful intercourse
    • Abnormal vaginal discharge
    • Infected pregnant women may have heavy bleeding before delivery and premature rupture of the membrane
  • For men:-
    • Pus or milky discharge from the penis
    • Prostatitis
    • Proctitis

Who should do the Chlamydia trachomatis test (Target population)?
Sexually active people or pregnant women having one or more of the above signs & symptoms.

What should I do before the Chlamydia trachomatis test?

Specimen type

Specimen collection procedure

Preparatory instructions during specimen collection*

Serum (Blood Sample)


Venipuncture - Collection of blood from a vein, usually from the arm.

No Fasting Required.

No other special preparations required.

*Subjects suffering from any illness or on oral or injectable medications are advised to consult their physician prior to requesting any tests or procedures.

How do I interpret my Chlamydia trachomatis test results?

Reference Range


Serum IgA

0 to 1.0 Index


Serum IgG

0 to 1.0 Index


Serum IgG

0 to 1.0 Index


Inference: A positive test indicates an active infection that requires treatment with a course of antibiotics. A negative test means only that there is no evidence of disease at the time of the test. It is important for those who are at increased risk of infection to have screening tests performed on a regular basis to check for possible exposure, especially since re-infection is common, particularly among teenagers. If you are infected, your sexual partner(s) should also be tested and treated as well.
‘*A Reference range is a set of values which helps the healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranges may also vary between labs, in value & units depending on instruments used and method of establishment of reference ranges’                       

Diseases/conditions related to the Chlamydia trachomatis test

  • Pelvic inflammatory disease (PID)
  • Infertility 
  • Tubal (ectopic) pregnancy
  • Cervicitis
  • Urethritis
  • Dysuria
  • Epididymitis
  • Prostatitis
  • Proctitis

Other tests related to the Chlamydia trachomatis test

  • Gonorrhea
  • Chlamydia pneumoniae