Background: The patient-administered tampon specimen has proven to be an easy and sensitive method for the diagnosis of genital Chlamydia trachomatis and Neisseria gonorrhoeae infections in women by polymerase chain reaction (PCR). This method avoids the need for endocervical sampling and stringent criteria for transport.
Goal: To evaluate two commercial amplification systems for the detection of C trachomatis and N gonorrhoeae from tampon specimens.
Study design: A group of 400 positive and negative tampon specimens tested by an in-house PCR method were selected from a pool of more than 2,000 previously collected tampons. Overall, 93 C trachomatis-positive and 77 N gonorrhoeae-positive specimens were evaluated. Each specimen was tested by Roche Cobas Amplicor and Abbott LCx (LCR), and results were compared to the in-house PCR method.
Results: Detection of C trachomatis by both assays was not significantly different from the in-house PCR assay. Fewer tampons were positive for N gonorrhoeae by LCR than either the in-house assay (P = 0.0001) or by Roche Amplicor (P = 0.01). However, tampon specimens tested by Roche Amplicor required DNA extraction to achieve comparative sensitivity.
Conclusion: Both commercial assays can be applied to tampon-collected specimens for automated detection of sexually transmitted diseases. The detection of C trachomatis was similar to the in-house PCR test for both assays (P = 0.73, 0.68). Detection of N gonorrhoeae resulted in fewer positive tampon specimens when tested by ligase chain reaction than both Roche Amplicor and in-house PCR.