You'll need a sample of the secretion from the urethra (in men) or the cervical canal (in women) to test for Chlamydia. Using immunofluorescent techniques, technicians detects Chlamydia antigens in the samples. Symptoms of Chlamydia can occur 7-14 days (incubation period) after infection. An immunofluorescent test, however, is quicker to detect an infection and can identify Chlamydia 3 days after possible infection (“the window period”) .