Comparison of three non-culture techniques for detection of Chlamydia trachomatis in genital tract specimens

A direct immunofluorescence (DIF) technique (Imagen) and two enzyme immunoassay (EIA) techniques (Chlamydiazyme and IDEIA) were compared for the detection of Chlamydia trachomatis in genital specimens from 502 attenders at a genitourinary medicine clinic. Eighty-two attenders were regarded as infected: 67 with positive results by at least two of the three techniques and 15 by virtue of elementary bodies detected in stored EIA buffer samples. With a positivity criterion of greater than or equal to 6 bodies Imagen was 76% sensitive for men and 61% sensitive for women. The sensitivity of Chlamydiazyme was 73% for men and 90% for women; comparative values for IDEIA were 80% and 71%, respectively. All three techniques were over 98% specific. Sampling order appeared to influence the sensitivity of IDEIA for specimens from men. All three techniques were less sensitive in the absence of cervicitis. The performances of the EIA techniques compared favourably with that of the more established technique of DIF.