Chlamydia screening--yes, but of whom, when, by whom, and with what?

The importance of screening programs in reducing the prevalence of genital chlamydial infections is stressed by the fact that the majority of infected persons are more or less asymptomatic. The use of oral contraceptives may mask infections affecting the upper genital tract. This imposes selective screening and rescreening of women with a history of pelvic inflammatory disease. The recent knowledge that vaginal introital samples will provide a detection rate equal to or even higher than that of cervical samples collected in the same women opens up the possibility of screening women in health units lacking a gynecological examination chair. It also opens up the possibility of outpatient screening programs, for example, home sampling and mailing samples to laboratories that will perform analyses. The use of nucleic acid-based assays means increased sensitivity and specificity compared with earlier used techniques such as ELISA. These former methods can also be used in low-prevalence populations with acceptable positive predictable value, but may be misleading if used in post-therapy check-ups because the antigen may persist in microbiologically cured cases.