Chlamydia Trachomatis (Swab)

Does this test have other names?

C. trachomatis test, CZ test, chlamydia test

What is this test?

This test looks for Chlamydia trachomatis bacteria in a sample of cells collected by your doctor.

C. trachomatis bacteria cause chlamydia. Chlamydia is one of the most common sexually transmitted infections (STIs) in the U.S.

The CDC recommends that sexually active women 25 and younger, as well as older women with risk factors, be screened once a year for chlamydia. That's because as many as half of women who get chlamydia don't have any symptoms. Men should be tested as soon as they have symptoms or if their partners are diagnosed with chlamydia.

In women, chlamydia may lead to cervicitis, an inflammation and swelling of the cervix. If it isn't treated, it can lead to serious sexual health problems, including infertility, pelvic inflammatory disease (PID), and may increase the chances of an ectopic pregnancy (pregnancy outside the womb). Affected women may also develop endometriosis. In men, chlamydia can cause urethritis. This is a swelling of the urethra and possibly blood in the urine. Babies born to mothers infected with chlamydia can get a lung or eye infection.

Chlamydia can be treated with antibiotics.

Why do I need this test?

You may need this test if you are a sexually active woman and you are:

  • Age 25 or younger.

  • An older woman with risk factors, such as:

    • You have new or multiple sexual partners.

    • You have sex with a partner who has an STI.

When symptoms happen in women, they can include:

  • Abnormal vaginal bleeding or discharge.

  • Belly or pelvic pain, or low back pain.

  • Pain during sex.

  • Pain when urinating.

  • Rectal pain.

When symptoms happen in men, they can include:

  • Watery discharge from your penis that's not urine. It is typically white or gray, or sometimes clear.

  • Pain when urinating.

  • Swollen scrotum.

  • Painful sensation in your testicles.

  • Rectal pain.

What other tests might I have along with this test?

Your doctor may also order other tests because chlamydia symptoms can be confused with symptoms of other STIs. These STIs include:

  • Gonorrhea.

  • HIV/AIDS.

  • Hepatitis B.

  • Trichomoniasis.

  • Syphilis.

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your doctor what your test results mean for you.

Normal results are negative, meaning that no chlamydia cells were found in your sample.

A positive result means that chlamydia bacteria were found and that you are likely infected with the disease. It is important to let any sexual partners know that you have tested positive for chlamydia so that they can be tested and treated if necessary.

How is this test done?

This test is done with a sample of cells from the urethra in males or the vagina in females. For men, the doctor will gently insert a swab 3 to 4 centimeters into the urethra. The doctor will turn it once to collect cells. For women, the doctor will put the swab or brush into the vagina to take cells from the cervix. For some cases, the rectum, cervix, throat, or eyes may be swabbed.

Does this test pose any risks?

This test poses no known risks.

What might affect my test results?

Other factors aren't likely to affect your results.

How do I get ready for this test?

You don't need to prepare for this test. Be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use. Ask your doctor if there are any special instructions for your test.

Online Medical Reviewer: Daphne Pierce-Smith RN MSN
Online Medical Reviewer: Raymond Turley Jr PA-C
Online Medical Reviewer: Vinita Wadhawan Researcher
Date Last Reviewed: 5/1/2025
© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.