Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in swab specimens by the hybrid capture II and PACE 2 nucleic acid probe tests

Background and Objectives: The Digene Hybrid Capture II (HC IT) CT/GC Test (Digene Corp., Beltsville, MD) is a new nucleic acid signal amplification-b ased test for the detection of Chlamydia trachomatis and Neisseria gonorrho eae in specimens from the genital tract. For optimal results, the HC II CT/ GC Test employs a special conical shaped brush for cervical specimen collec tion from nonpregnant women and swabs from pregnant women. Goals: To validate a protocol for HC II C, trachomatis and N. gonorrhoeae t esting of specimens collected for the GenProbe PACE 2 System. Study Design: Specimens were collected from 1,746 patients with a swab and placed in GenProbe transport media according to the manufacturer's recommen ded procedure. The specimens were first tested at two clinical laboratories by the PACE 2 system, and then blindly tested by HC II CT/GC using an adju sted cutoff value. Discrepant specimens were adjudicated by polymerase chai n reaction (PCR), and the result common to two of the three testing methods (HC II, PACE 2, and PCR) was defined as the consensus result, Results: Combining the data from both sites, the relative sensitivity of th e HC II Test compared with the consensus result for the detection of 1,761 specimens for C, trachomatis and 1,750 specimens for N. gonorrhoeae was 100 % for both organisms. The relative specificities for C, trachomatis and N, gonorrhoeae detection were 99.8% and 99.7%, respectively. The relative sens itivities of the PACE 2 CT and GC Systems were 86.5 % and 87.1%, respective ly, with relative specificities of 99.9% and 100%, The difference in sensit ivity between HC II and PACE 2 for C, trachomatis detection was significant (P < 0.016), Conclusion: The HC II CT/GC Test can be performed using specimens collected in GenProbe transport media and has a significantly greater sensitivity fo r C, trachomatis detection than the PACE 2 System.