Evaluation of self-collected samples in contrast to practitioner collected samples for detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis by polymerase chain reaction among women living in remote areas

Background: Self-collected samples have been shown to be an acceptable and sensitive method for the detection by polymerase chain reaction (PCR) of sexually transmitted infections (STIs) among women. Goal: The goal of the study was to compare self-collected sampling methods to conventional practitioner endocervical sampling for the PCR detection of Chlamydia trachomatis and Neisseria gonorrhoeae and to compare two self-collected sampling methods for the detection of T vaginalis by PCR. Study Design: Women (n = 318) from urban and remote areas of central Australia participated in the study when attending their health clinic for a check-up. They each provided a FVU sample, self-collected vaginal swab specimen, and tampon specimen. This was followed by a clinical examination by a practitioner, with collection of endocervical and high vaginal swabs for testing by conventional microscopy and culture for N gonorrhoeae and T vaginalis, respectively. The FVU, self-collected vaginal swab, tampon, and endocervical swab specimens were tested by Roche Cobas Amplicor for C trachomatis and N gonorrhoeae. The self-collected vaginal swab and tampon specimens were also tested by an in-house PCR method for the detection of T vaginalis. Results: In toto, C trachomatis was detected by PCR in 11.5%, N gonorrhoeae in 11.8%, and T vaginalis in 24.6%. Molecular diagnostics for N gonorrhoeae and T vaginalis were significantly more sensitive than traditional assays with microscopy and culture. For the detection of C trachomatis by PCR, tampons were the most sensitive (100.0%) and urine the least sensitive (72.7%) specimens (P = 0.01). For the detection of N gonorrhoeae by PCR, the self-collected tampon was the most sensitive specimen, followed by the endocervical swab, self-collected swab, and urine specimen, with sensitivities of 97.2%, 92.6%, 71.9%, and 31.2%, respectively. For detection of N gonorrhoeae, statistically significant differences were detected for urine versus tampon (P < 0.0001), endocervical swab (P < 0.001), and self-collected swab (P = 0.01) and for self-collected swab versus tampon (P = 0.01). Subsequent data collection showed that sensitivity of urine PCR for detection of N gonorrhoeae improved with freezing of urine specimens and shorter transport time. Tampons were also more sensitive than self-collected swabs for detection of T vaginalis (sensitivity of 100% versus 87.7%). Conclusion: Self-collected specimens offer women in remote communities an acceptable and sensitive alternative method of testing for STIs. The low sensitivity of N gonorrhoeae PCR of urine specimens may reflect poor transport and storage conditions, which we have shown can be improved by freezing urine specimens and reducing transport delays.