Recently, test developers created rapid point-of-care tests that can detect multiple infections with the same specimen using a single device. The SD BIOLINE Duo HIV/Syphilis rapid point-of-care test uses a solid phase immunochromatographic assay to detect IgG, IgM and IgA antibodies to HIV specific antigens (HIV-1 gp41, sub O, HIV-2 gp36) and recombinant Treponema (T.) pallidum antigens (17KDa) in human serum. This study was a multisite laboratory-based evaluation of performance of the SD Bioline HIV/Syphilis Duo test using well- characterized sera in six countries.
Laboratories in Ghana, Mexico, Laos, Togo, Kenya, and Myanmar participated in the evaluation in 2012 and 2013. Each site characterized sera using a combination of T. pallidum particle agglutination assay or T. pallidum Hemaglutination Assay and HIV enzyme immunoassay, Western Blot, and HIV antibody rapid tests. Those gold standard test results were compared with SD BIOLINE Duo test results. Because of the lack in heterogeneity of performance between sites we combined the data and calculated the sensitivity and specificity of test performance. We used the exact binomial method to calculate 95% confidence intervals (CI).
The combined sensitivity and specificity for the HIV antibody component (N=2336) were estimated at 99.91% (95% CI: 99.51%, 100%) and 99.67% (95% CI: 99.16, 99.91%), respectively. For the T. pallidum component (N=2059), the combined sensitivity and specificity were estimated at 99.67% (95% CI: 98.82%, 99.96%) and 99.72% (95% CI: 99.29%, 99.92%), respectively.
The sensitivity and specificity of the SD Bioline HIV/Syphilis Duo test using serum was consistently high across sera specimens from 6 countries around the world. This dual test could be a timely breakthrough for the UNAIDS and WHO strategy for dual elimination of maternal-to-child transmission of HIV and syphilis. Dual rapid tests should be considered for improved HIV and syphilis screening coverage.