Skip to content
My WebMD Sign In, Sign Up

Sexual Conditions Health Center

Font Size

Chlamydia Tests

Chlamydia tests use a sample of body fluid or urine to see whether chlamydia bacteria (Chlamydia trachomatis) are present and causing an infection. Chlamydia is the most common bacterial sexually transmitted infection (STI) in the United States.

Several types of tests can be used to find a chlamydia infection. Most tests use a sample of body fluid from the affected area.

  • Nucleic acid amplification tests (NAAT). These tests find the genetic material (DNA) of chlamydia bacteria. These tests are very good at identifying chlamydia. A test that is positive almost always means the problem is there and is unlikely to be a false-positive test result. A polymerase chain reaction (PCR) test is an example of a nucleic acid amplification test. This test can also be done on a urine sample.
  • Nucleic acid hybridization tests (DNA probe test). A probe test also finds chlamydia DNA. A probe test is very accurate but is not as sensitive as nucleic acid amplification tests.
  • Enzyme-linked immunosorbent assay (ELISA, EIA). This quick test finds substances (chlamydia antigens) that trigger the immune system to fight chlamydia infection.
  • Direct fluorescent antibody test (DFA). This quick test also finds chlamydia antigens.
  • Chlamydia culture. A culture is a special cup that allows the chlamydia bacteria to grow. Results take longer (5 to 7 days) than the other tests. The culture must be done in a lab.

Why It Is Done

A test for chlamydia is done to:

  • See whether symptoms of a sexually transmitted infection (STI) are caused by a chlamydia infection.
  • Check people who are at high risk for being infected with chlamydia. A chlamydia infection does not always cause symptoms. The U.S. Preventive Services Task Force (USPSTF) recommends checking for chlamydia for:
  • Check for infection in a newborn whose mother had a chlamydia infection at the time of delivery.

How To Prepare

A chlamydia test is done on either a urine sample or fluid (direct sample) collected from the area of the body that is most likely to be infected. If your chlamydia test is being done on a:

  • Urine sample: Do not urinate for 2 hours before a urine sample is collected.
  • Direct sample (usually from the cervix): A woman should not douche or use vaginal creams or medicines for 24 hours before having a chlamydia test.

WebMD Medical Reference from Healthwise

Last Updated: December 11, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Today on WebMD

Sex Drive Killers 03
Slideshow
couple holding hands
Quiz
 
Couple in bed
Article
Condom Quiz
Quiz
 

HIV Myth Facts
Slideshow
STD Overview
Slideshow
 
exercise
Video
things your guy wish you knew slideshow
Slideshow
 

Thoughtful man sitting on bed
Quiz
Girls Puberty 10
Quiz
 
Couple in bed
Article
Young couple holding hands
Quiz
 

WebMD Special Sections