CHLAMYDIAL INFECTION IN A HIGH-RISK POPULATION - COMPARISON OF AMPLICOR PCR AND GEN-PROBE PACE-II FOR DIAGNOSIS

The objective of this study was to compare the sensitivities and speci ficities of two molecular techniques, polymerase chain reaction (Ampli cor) and DNA hybridization probe (Gen-Probe PACE II), for the detectio n of Chlamydia trachomatis in cervical specimens. A total of 378 cervi cal specimens were collected from 189 female adolescent patients and t ested with either Amplicor or Gen-Probe PACE II. Sociodemographic data and sexually transmitted disease risk behavior were also collected fr om patient charts and analyzed. The population comprised young adolesc ents (mean age 17.7) who were sexually active (77.1% had one or more p artners in the last 3 months) with a relatively long duration of sexua l activity (mean 2.8 years). The prevalence rates of cervical C. trach omatis infection diagnosed by Amplicor and Gen-Probe PACE II were 7.9 and 9.0%, respectively. Patients testing positive for C. trachomatis h ad a significant percentage of Pap smears with inflammatory results (p < 0.005). After initial testing, Amplicor had a sensitivity of 82.4% and a specificity of 93.3%, whereas Gen-Probe PACE II had a sensitivit y of 99.4% and a specificity of 98.3%. After discrepant analysis, Ampl icor and Gen-Probe PACE II had an equal sensitivity of 93.7%; the spec ificities were 100 and 98.8%, respectively. However, Gen-Probe PACE II had a 1% false-positive rate. Both Amplicor and Gen-Probe PACE II are highly sensitive. However, Amplicor is more specific and can be used as a confirmatory test. Either test for C. trachomatis may be indicate d in patients with abnormal Pap smears.