A comparison of an enzyme immunoassay and cell culture for detection of Chlamydia trachomatis in genito-urinary specimens.

Chlamydia trachomatis infection is easy to treat but laborious to diagnose by culture. An antigen-detecting enzyme immunoassay (EIA; Chlamydiazyme, Abbott Laboratories, North Chicago, IL), suitable for testing many samples, was compared with the conventional iodine-stained, one-passage culture. A total of 471 duplicate samples from 218 men (urethra) and 128 women (urethra and cervix) attending a sexually transmitted disease clinic were examined by both tests. The overall sensitivity, specificity, and predictive value of positive and negative results were 80.3%, 96.7%, 86.4%, and 95.0%, respectively. No difference between male and female patients was observed. A remarkable difference between sensitivities of female urethral (60.0%) and cervical (95.5%) samples was found. This difference is clearly important in cases of women with urethral infection only (19% in our study) and points to the need for further improvement of this EIA.