Performance characteristics of the Becton Dickinson ProbeTec System for direct detection of Chlamydia trachomatis and Neisseria gonorrhoeae in male and female urine specimens in comparison with the Roche Cobas system

Objective.-The Becton Dickinson BDProbeTec ET System is a new semiautomated system using strand displacement amplification technology that simultaneou sly amplifies and detects Chlamydia trachomatis and Neisseria gonorrhoeae D NA. The strand displacement amplification products are hybridized with a fl uorescent detector probe and are captured by a chemiluminescent assay in a microwell format. An amplification control is also included to monitor assa y inhibition. This study evaluated the performance of the BDProbTec ET syst em in detecting C trachomatis and N gonorrhoeae in male and female urine sp ecimens, calculated its ability to process large volumes of specimens, and determined the inhibition rate. Materials and Methods.-Eight hundred twenty-five male and 399 female urine specimens were tested for both C trachomatis and N gonorrhoeae with the BDP robeTec ET system, and results were compared with those of the Roche Amplic or Cobas system. All urine specimens were processed on both assays on the s ame day they were received, according to the manufacturers' instructions. D iscrepant results were resolved by in-house polymerase chain reaction assay s. Internal or amplification controls were also used in each specimen assay to monitor inhibition. The throughput of the BDProbTec ET system was furth er tested with 150 urine specimens on an 8-hour shift for 2 days. Results.-The overall sensitivity, specificity, positive predicative value, and negative predicative value for for detection of chlamydia were 95.3%, 9 9.3%, 95.9%, and 99.2% for strand displacement amplification and 95.9%, 98. 3%, 90.6%, and 99.3% for the Roche Amplicor system. For detection of gonorr hea, these values were 100%, 99.7%, 88.2%, and 100% and 96.7%, 98.9%, 69%, and 99.9%, respectively. The overall inhibition rates for both strand displ acement amplification and Roche Amplicor were less than 3.5%. The BDProbTec ET system was able to produce 150 results each for chlamydia and gonorrhea and the internal control within the 8-hour shift. Conclusions.-The performance characteristics of the BDProbeTec ET assay are similar to those of the Roche Amplicor polymerase chain reaction for detec tion of chlamydia and gonorrhea in male and female urine specimens. The sys tem was able to produce 300 results in an 8-hour shift.