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
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
Direct fluorescent antibody test (DFA). This quick test also finds chlamydia
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.
women in the first trimester and again in the third trimester if high-risk
sexual behaviors are reported. Treating a pregnant woman who has a chlamydia
infection can prevent an infection in her newborn.