Male Urethral Swab Specimens Research Articles

Clinical Evaluation of the BD ProbeTec™ Neisseria gonorrhoeae Qx Amplified DNA Assay on the BD Viper™ System With XTR™ Technology

The excellent sensitivity and specificity of commercially available nucleic acid amplification tests (NAATs) for the identification of Neisseria gonorrhoeae have been demonstrated. This study evaluated the performance of the BD ProbeTec™ N. gonorrhoeae Q (GCQ) Amplified DNA Assay on the BD Viper™ System with XTR™ Technology in a multicenter study. Specimens were collected at 7 geographically diverse clinical sites from 1846 women and men attending sexually transmitted disease, family planning, and obstetrics and gynecology clinics. There were 1768 evaluable participants, 994 women and 774 men. GCQ results from female endocervical, self-collected vaginal, male urethral swab specimens, and male and female neat (unpreserved) urine specimens, as well as those obtained using the urine preservative transport (UPT) tube for the GCQ assay were compared with patient infected status (PIS). For each participant, PIS was determined based on the combined results from the reference assays Aptima Combo 2® (AC2) and BD ProbeTec™ ET GC Amplified DNA Assay (PT). The sensitivity versus PIS for endocervical, vaginal, and female UPT urine, and female neat urine samples was 98.5%, 100.0%, 98.5%, and 96.9%, respectively; the specificity was 99.7%, 99.1%, 99.7%, and 99.5%, respectively. The sensitivity versus PIS for male urethral swabs and both male UPT and neat urine was 100.0%, with specificities of 99.1% for the urethral swab and UPT urine and 98.9% for the neat urine. The overall GCQ assay performance was not statistically different from that of AC2 or PT. The GCQ assay demonstrated performance characteristics comparable with other commercially available nucleic acid-based tests such as AC2 and PT. Vaginal swabs, endocervical swabs, urethral swabs, and urine specimens may all be used for gonorrhea screening.

Clinical Evaluation of the BD ProbeTec™ Chlamydia trachomatis Qx Amplified DNA Assay on the BD Viper™ System With XTR™ Technology

This study evaluated the performance of the BD ProbeTec Chlamydia trachomatis Q (CTQ) Amplified DNA Assay on the BD Viper System with XTR Technology in a multicenter study. Specimens were collected at 7 geographically diverse clinical sites from 1538 women and men attending sexually transmitted disease, family planning, and obstetrics and gynecology clinics. There were 1465 evaluable participants, 993 women and 472 men. CTQ assay results from female endocervical, self-collected vaginal, male urethral swab specimens, and male and female neat (unpreserved) urine specimens as well as those obtained using the Urine Preservative Transport (UPT) tube for the CTQ assay were compared with patient-infected status (PIS). PIS was determined based on the combined results from Aptima Combo 2 and BD ProbeTec ET CT Amplified DNA Assay. The sensitivity versus PIS for endocervical, vaginal, and both female urine samples was 91.3%, 96.5%, and 93.0%, respectively. The specificity for the same specimen types was 98.3%, 99.2%, and 99.4% (urine neat) and 99.2% (UPT), respectively. The sensitivity versus PIS for male urethral swabs and both male neat and UPT urine were 92.1% and 98%, respectively, with specificities of 98.4%, 99.2%, and 98.1%, respectively. The CTQ assay demonstrated performance characteristics comparable with other commercially available nucleic acid-based tests such as Aptima Combo 2 and BD ProbeTec ET CT-Amplified DNA assay. Vaginal swabs and male urine specimens, the sample types recommended by the Centers for Disease Control for chlamydia screening, both performed at least as well as other sample types evaluated.

Ligase chain reaction for detection of Neisseria gonorrhoeae in urogenital swabs

The ligase chain reaction (LCR) is an in vitro nucleic acid amplification technique that exponentially amplifies targeted DNA sequences. In a multicenter study, we evaluated the use of a 4-h LCR-based assay for the diagnosis of Neisseria gonorrhoeae infection of the cervix and male urethra. The LCR results were compared with those of culture for N. gonorrhoeae by using selective media. This assay amplifies target sequences within the N. gonorrhoeae opacity gene. Discordant LCR-positive and culture-negative specimens were further evaluated by testing by another LCR assay which used N. gonorrhoeae-specific pilin probe sets. A total of 1,539 female endocervical specimens and 808 male urethral swab specimens were evaluated in the study. An expanded "gold standard" was defined to include all culture-positive as well as culture-negative, confirmed LCR-positive specimens. After resolution of discrepant samples, the sensitivities of the N. gonorrhoeae LCR assays for the female and male specimens were 97.3 and 98.5%, respectively, with specificities of 99.6 and 99.8%, respectively. Resolved culture sensitivities were 83.9 and 96.5% for the female and male specimens, respectively. The LCR assay for gonorrhea is a rapid, highly sensitive nonculture method for detecting gonococcal infection of the cervix and male urethra.

Use of PCR and direct immunofluorescence microscopy for confirmation of results obtained by Syva MicroTrak Chlamydia enzyme immunoassay

A procedure for use of the Amplicor Chlamydia PCR with the Syva MicroTrak enzyme immunoassay (EIA) medium was developed, and the performance of the Syva MicroTrak EIA was evaluated by use of PCR and the Syva MicroTrak direct immunofluorescence assay (DFA) as confirmatory methods. PCR detected Chlamydia organisms at a 10-fold greater dilution than did DFA. Of 366 specimens, 119 specimens were positive by both PCR and DFA, 6 specimens were positive only by PCR, and 241 specimens were negative by both PCR and DFA. Subsequently, DFA and the developed PCR procedure were used prospectively for confirmation of EIA results in a defined negative gray zone between the cutoff value and 30% of the cutoff value (70% below the cutoff value). All specimens with results above the EIA cutoff value were also subjected to confirmation with DFA and PCR. EIA was performed on 7,748 endocervical swab specimens, of which 494 (6.4%) were subjected to confirmation, and on 968 male urethral swab specimens, of which 185 (19.1%) were subjected to confirmation. A "gold standard" was based on the findings by DFA and PCR, and divergent results were resolved by a major outer membrane protein-based PCR. Forty-five of 160 female specimens (28.1%) and 11 of 93 male specimens (11.8%) within the defined negative gray zone were found to be positive. Of 334 female specimens having absorbance unit (AU) values above the EIA cutoff value, 258 could be confirmed, thereby giving a positive predictive value of 77% (258/334). Accordingly, the positive predictive value with male specimens was 95% (87/92). The prevalence of Chlamydia trachomatis-positive specimens was 3.9% (303/7,748) in females and 10.1% (98/968) in males. All male specimens having AU values above 1.0 in the EIA were confirmed positive. In contrast to this, 16 females with AU values above 1.0 in the EIA could not be confirmed positive with either DFA or PCR. The mean age of these females was higher than that of patients testing negative for C. trachomatis (P < 0.005). This might suggest an age-dependent change in vaginal colonization with an organism(s) crossreacting in the EIA. Thus, the PCR procedure developed can be used for confirmation of EIA results, testing specimens with AU values in the defined negative gray zone improves the sensitivity of EIA, and all specimens testing positive in EIA should be subjected to confirmation.