Chlamydia trachomatis is often called “the silent epidemic.”


Chlamydia is a sexually transmitted disease (STD). Chlamydia trachomatis is often called “the silent epidemic” because infections are common yet many people do not realize that they are infected.

This bacterial disease is easily cured with antibiotics but can have serious health consequences if left untreated.

Why get tested for chlamydia?

To screen for or diagnose chlamydia infection

When to get tested?

If you are sexually active, pregnant, have one or more risk factors for developing chlamydia, or have a cervical infection; depending on your risk factors, may be annually

Sample required? A swab of cells or secretion from the infected area.

The test is used in two ways:

  1. to diagnose the cause of symptoms, and
  2. to screen sexually active people for the bacterium.

A definitive diagnosis is important because chlamydia can resemble gonorrhea, and the two infections require different antibiotic treatment.

When is it ordered?

A doctor may order the test if you have symptoms such as vaginal discharge and abdominal pain (for women) or unusual discharge from the penis or pain on urination (for men). However, about 75% of infected women and 50% of infected men show no active symptoms, so the Centers for Disease Control recommend testing in the following cases:

  • All sexually active females under 20 years of age (test at least once a year).
  • Women ages 20 and older who have one or more risk factors (test annually). Risk factors include having new or multiple sex partners, having sex with someone who has other partners, and not using barrier contraceptives, such as condoms.
  • All women with an infection of the cervix.
  • All pregnant women.


What does the test result mean?

A positive test indicates an active infection that requires treatment with a course of antibiotics.

Is there anything else I should know?

Chlamydia is often called “the silent epidemic” because infections are so prevalent yet many people do not know that they are infected. An estimated 3 million cases occur annually in the U.S. Chlamydia is especially widespread among young people under the age of 25. It is four times as common as gonorrhea and six times as common as herpes.

Chlamydia is easily treated, but if left untreated, it can cause severe reproductive and other health problems. If you are infected, your sexual partner(s) should also be tested and treated as well.

People who are infected have a higher risk of developing other sexually transmitted diseases, including a 3 to 5 times greater risk of acquiring HIV if exposed to it.

The diagnosis of a sexually transmitted disease should not be ruled out just because the test is negative; patients' clinical symptoms and history should also be considered.