Background:
An Internet-based screening program, www.iwantthekit.org, designed to educate and screen women for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG), offered home self-sampling kits.

Objective:
To evaluate the performance of three NAATs used to detect CT and NG.

Method:
From July 2004 to August 2005, 500 self-collected vaginal swabs were tested for CT and NG by Becton-Dickinson ProbeTec™ SDA, Gen-Probe® APTIMA® Combo2 TMA, and Roche Amplicor® PCR. Each swab was expressed in 800µl Tris-EDTA buffer; 200µl was placed into SDA diluent, 200µl was placed into TMA swab transport medium, and 200µl was DNA-extracted using MagNA Pure®LC. All tests were conducted according to manufacturers' procedures. The gold standard for a CT or NG infected patient was defined as >2 positive NAATs.

Result:
Of 500 swabs submitted, 46 were CT infected (9.2%), 5 NG infected (1.0%), and 3 of these were co-infected (0.6%). CT: ProbeTec had a sensitivity and specificity of 82.6% (38/46) and 100% (454/454), respectively. Combo 2 had a sensitivity and specificity of 100% (46/46) and 100% (454/454), respectively. PCR had a sensitivity and specificity of 100% (46/46) and 99.3% (451/454), respectively. GC: ProbeTec had a sensitivity and specificity of 80% (4/5) and 100% (495/495), respectively. Combo 2 had a sensitivity and specificity of 100% (5/5) and 100% (495/495), respectively. PCR had a sensitivity and specificity of 100% (5/5) and 98.8% (489/495), respectively. Overall, PCR had 3 CT false positives (0.6%) and 6 NG false positives (1.2%). Additionally, ProbeTec had 8 CT false negatives (1.6%) and one NG false negative (0.2%).

Conclusion:
Our results were consistent with the sensitivities and specificities stated by the manufacturers. Use of confirmatory testing can increase sensitivity and decrease the likelihood of false positives. Self-collected vaginal swabs appear to be suitable specimens for NAAT testing for chlamydia and gonorrhea.

Implications:
Self collected vaginal samples are suitable specimens for NAAT testing.