Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by enzyme immunoassay, culture, and three nucleic acid amplification tests

The purpose of this study was to evaluate and compare three commercially av ailable nucleic acid amplification tests (NAATs) for the detection of Neiss eria gonorrhoeae and Chlamydia trachomatis. Roche PCR and Becton Dickinson strand displacement amplification (SDA) were performed on 733 endocervical swab specimens from commercial sex workers. Abbott ligase chain reaction (L CR) was performed on a subset of 396 samples. Endocervical specimens from a ll women were also tested by culture for N. gonorrhoeae and by Syva MicroTr ak enzyme immunoassay (EIA) for C. trachomatis. A positive N. gonorrhoeae r esult was defined as a positive result by culture or by two NAATs, and a po sitive C. trachomatis result was defined as a positive result by two tests. According to these definitions, the sensitivities and specificities for th e subsample of 396 specimens of N. gonorrhoeae culture, PCR, SDA, and LCR w ere 69.8, 95.2, 88.9, and 88.9% and 100, 99.4, 100, and 99.1%, respectively ; the sensitivities and specificities of C. trachomatis EIA, PCR, SDA, and LCR were 42.0, 98.0, 94.0, and 90.0% and 100, 98.0, 100, and 98.6%, respect ively. The performance characteristics of N. gonorrhoeae culture, PCR, and SDA and C. trachomatis EIA, PCR, and SDA for all 733 specimens were defined without inclusion of LCR results and by discrepant analysis after resoluti on of discordant N. gonorrhoeae PCR results and of discordant C. trachomati s EIA and PCR results by LCR testing. The sensitivities of N. gonorrhoeae c ulture, PCR, and SDA before and after LCR resolution were 67.8, 95.7, and 9 3.9% and 65, 95.8, and 90:0%, respectively. The sensitivities of C. trachom atis EIA, PCR, and SDA decreased from 39.4, 100, and 100% to 38.7, 98.7, an d 94.7%, respectively. All three NAATs proved to be superior to N. gonorrho eae culture and to C. trachomatis EIA. The accuracies of the different NAAT s were quite similar. SDA was the only amplification assay with 100% specif icity for detection of both N. gonorrhoeae and C. trachomatis in endocervic al specimens.