Multicenter Evaluation of AMPLICOR and Automated COBAS AMPLICOR CT/NG Tests for Neisseria gonorrhoeae

Abstract

The fully automated COBAS AMPLICOR CT/NG and semiautomated AMPLICOR CT/NG tests were evaluated in a multicenter trial for their ability to detect Neisseria gonorrhoeae infections. Test performance compared to that of culturing was evaluated for 2,192 matched endocervical swab and urine specimens obtained from women and for 1,981 matched urethral swab and urine specimens obtained from men. Culture-negative, PCR-positive specimens that tested positive in a confirmatory PCR test for an alternative target sequence within theN. gonorrhoeae 16S rRNA gene were considered to be true positives. The overall prevalences of gonorrhea were 6.6% in women and 20.1% in men. The COBAS AMPLICOR and AMPLICOR formats yielded concordant results for 98.8% of the specimens and exhibited virtually identical sensitivities and specificities. The results that follow are for the COBAS AMPLICOR format. With the infected patient as the reference standard, the resolved sensitivities of PCR were 92.4% for endocervical swab specimens and 64.8% for female urine specimens. There were no significant differences in these rates between women with and without symptoms. Among symptomatic men, COBAS AMPLICOR sensitivities were 94.1% for urine and 98.1% for urethral swabs; for asymptomatic men, the results were 42.3 and 73.1%, respectively. In comparison, the sensitivities of culturing were 84.8% for endocervical specimens, 92.7% for symptomatic male urethral specimens, and only 46.2% for urethral specimens obtained from asymptomatic men. When PCR results were analyzed as if only a single test had been performed on a single specimen type, the resolved sensitivity was always higher. The resolved specificities of PCR were 99.5% for endocervical swab specimens, 99.8% for female urine specimens, 98.9% for male urethral swab specimens, and 99.9% for male urine specimens. The internal control revealed that 2.1% of specimens were inhibitory when initially tested. Nevertheless, valid results were obtained for 99.2% of specimens because 60.0% of the inhibitory specimens were not inhibitory when a second aliquot was tested. The COBAS AMPLICOR CT/NG test for N. gonorrhoeae exhibited high sensitivity and specificity with urethral swab and urine specimens from men and endocervical swab specimens from women and thus is well suited for diagnosing and screening for N. gonorrhoeae infection.

Verification of clinical samples, positive in AMPLICOR Neisseria gonorrhoeae polymerase chain reaction, by 16S rRNA and gyrA compared with culture

“…Culture also requires skilled laboratory technicians, which can be a problem, especially when it comes to low prevalence diseases. The fact that every laboratory uses a local definition of sensitivity was clearly illustrated in a study by Martin et al, where sensitivity was influenced by what is described as " exceptionally poor performance" of 1 JRQRUUKRHDH culture in one of the six laboratories [155]. The same conclusion was drawn by van Dyck et al when comparing the sensitivity of 1 JRQRUUKRHDH culture, which was described as " extremely low" , in two of the three laboratories in their study [146].…”

“…Confirmation [138, 142, 144-146, 155, 157, 174] Conditional confirmation: if discrepant results [149,178,179] if asymptomatic [155] if culture negative [155,174] Rerun in same method [155] A future molecular 1 JRQRUUKRHDH test with acceptable specificity probably will be considered as a diagnostic tool also in populations with a low prevalence of gonorrhea. For example, when the clinician today chooses to test only for & WUDFKRPDWLV, or when a patient with risk behavior has no symptoms, but wishes to be tested, a molecular test also for 1 JRQRUUKRHDH could add valuable information.…”

“…Probably this sample collection would work also for 1 JRQRUUKRHDH. It is of importance that the future test has an acceptable sensitivity also in urine samples from females; this sampling technique has been shown to have decreased sensitivity [149,155,157], but urine or vaginal swab in urine might prove sufficient for screening purposes.…”

Susceptibility of Middle Adolescent Females to Sexually Transmitted infections: Impact of Hormone Contraception and Sexual Behaviors on Vaginal Immunity

“…The presence of CT, TV, and GC was examined for each patient at each visit using polymerase chain reaction (PCR) using the COBAS AMPLICOR CT/NG test and a modification of this assay to test for TV from vaginal swabs 12,13 (B. Van Der Pol, J.A.…”

A comparison of three real-time PCR assays for the confirmation of Neisseria gonorrhoeae following detection of N. gonorrhoeae using Roche COBAS AMPLICOR

“…All of the clinical specimens included in this study were initially assayed by the COBAS AMPLICOR duplex assay for C. trachomatis and N. gonorrhoeae. This assay has been validated for urethral and endocervical swabs and for urine specimens, with sensitivities of 92.4-100% for swabs and of 42.3-94.1% for urine, and with specificities of 95.9-99.9% for all three types of specimen [8,9,13,15,[19][20][21][22][23]. However, a major drawback of this assay is its reported crossreactivity with other Neisseria spp.…”