PCR and direct fluorescent-antibody staining confirm Chlamydia trachomatis antigens in swabs and urine below the detection threshold of Chlamydiazyme enzyme immunoassay

In order to test the hypothesis that specimens blocking with a neutralizing reagent below the cutoff of the Chlamydiazyme enzyme immunoassay represent infected patients, we used direct fluorescent-antibody staining for elementary bodies (EBs) and PCR to confirm results for cervical swabs collected from 55,963 women and urethral swabs or first-void urine (FVU) samples collected from 5,781 men attending physicians' offices in the Toronto, Canada, …