Performance of the APTIMA assay
The accuracy of the Gen-Probe APTIMA system in published studies is in the range of 98–100%, but we performed our own validation of the APTIMA system to insure good performance for testing of BC patients. Cooperating clinics collected dual Gen-Probe APTIMA and BD ProbeTec swabs that were tested in parallel on the two systems. We also tested urine specimens on the two systems. Discrepancies were resolved by repeat testing on both systems and by testing using alternative DNA amplification methods. 1534 specimens were tested by both methods for Chlamydia and gonorrhea. A total of 269 specimens were positive for one or both organisms, and the APTIMA system demonstrated >99% sensitivity and specificity overall for both swab and urine specimens compared to the BD ProbeTec system. The results by specimen type are shown above. Based on this excellent performance, the Gen-Probe APTIMA system was chosen for implementation.