Background:
The fight against mother-to-child transmission of HIV, syphilis and hepatitis B is a priority for the Cameroon government. The availability of combined rapid diagnostic tests (RDTs) for these three diseases is helping to achieve this triple elimination. The aim of this study was to evaluate the performance of a combined HIV and syphilis screening test (SD Bioline HIV/syphilis Duo) in Yaoundé and Douala, Cameroon.
Material and method:
This ethically approved cross-sectional study (N° 2022/08/1478 CE/CNERSH/SP) was conducted from 03 to 29 June 2023, in 74 health facilities (selected according to their ANC weight) in 15 Health Districts of the cities of Yaoundé and Douala. The study population consisted of pregnant women (PWs) of unknown HIV and syphilis status, aged 15 years and over, recruited by accidental sampling in ANC and maternity wards. Parallel and serial combinations of the Détermine, Oraquick, TPHA and VDRL tests were used as a reference to assess the sensitivity and specificity of the Duo test on venous blood samples. Inter-operator reproducibility of the Duo test was assessed between trained maternity/ANC staff and those in the health facility laboratories using Cohen's Kappa (K).
Results:
For HIV, out of 4108 PWs with a median age of 27 years, 1.46% were positive, with similarities between Yaoundé (1.47%) and Douala (1.45%). Sensitivity was 83.6% (95%IC:73.2-90.4) and specificity was 99.4% (IC95%:99.1-99.6); reproducibility was moderate with K=0.586 (95%IC:0.266-0.267) and p=0.0000.
For syphilis, 0.24% of 1228 PWs were positive. Sensitivity was 100% (IC95%:38.0 - 100) and specificity was 99.8% (IC95%:99.4 - 100); reproducibility was poor with K=0.170 (95%CI:0.1695-0.1704), p=0.0000. None of the PWs had been screened for co-infection with HIV and syphilis.
Conclusion: The value of using the SD Bioline HIV/syphilis Duo combined test lies in its ability to detect syphilis when it is performed by the technician laboratory.