Evaluation of a rapid point-of-care test for the detection of gonococcal infection among female sex workers in Benin

Objectives: To assess the validity of the PATH ( Seattle, Washington, USA) GC-Check rapid test, a point-of-care immunochromatographic strip test, in the detection of gonococcal infection among female sex workers (FSWs) in Benin. Methods: Women consulting consecutively at two FSW-dedicated clinics in Cotonou and Porto Novo ( Benin) were recruited over three, 1-month periods between October 2003 and July 2004. After written informed consent, participants were administered a short interview and underwent a speculum examination where two cervical swabs were collected ( in a subset of women, a vaginal swab was also collected). One cervical swab and the vaginal swab were immediately tested with the rapid test. The other cervical swab was frozen at 20 C for at most four weeks and then transported to Quebec ( Canada), where it was tested with the Roche Amplicor CT/NG PCR assay. Samples positive for gonococcal infection were confirmed using a 16SrRNA PCR assay. Results: 1084 FSWs ( median age 29 years) participated in the study, of whom 50 ( 4.6%) had a confirmed gonococcal infection. The sensitivity, specificity, positive and negative predictive values of the rapid test on cervical samples were 70.0% (95% confidence interval (CI) 55.4% to 82.1%), 97.2% ( 95% CI 96.0% to 98.1%), 54.7% and 98.5%, respectively. The sensitivity of the rapid test on vaginal swabs among 759 women ( 37 positives for gonococcal infection) was significantly lower than with the cervical swab (54.1%, p = 0.008), whereas the specificity was comparable (98.2%, p = 0.13). Conclusions: The PATH GC-Check test may be as efficient as a gold standard polymerase chain reaction ( PCR) test for treating gonococcal infection when taking into account the proportion of women who do not return for their test results. In clinics serving populations with moderate prevalence of this infection, it could significantly reduce over-treatment compared to the syndromic approach.