Diagnostic performance evaluation of the Abbott Bioline™ HIV/Syphilis Duo rapid test at the national public health laboratory, Yaounde-Cameroon

The Bioline™ HIV/Syphilis Duo rapid diagnostic test (RDT) is the first World Health Organization (WHO) prequalified Duo RDT for the simultaneous detection of human immunodeficiency virus (HIV) and Treponema pallidum antibodies in human blood samples. Several studies have shown the satisfactory diagnostic performance of this test among vulnerable populations such as pregnant women. However, the diagnostic performance of this Duo test is scarce in the general population in Cameroon. The present study aimed to assess the diagnostic performance of the Abbot Bioline™ HIV/Syphilis Duo RDT in Cameroon. A laboratory based cross-sectional and comparative study was conducted from January, 6th to June, 19th 2024 on serum/plasma collected from adult individuals (aged: ≥ 21 years), recruited consecutively in health facilities in eight regions of Cameroon. The blood samples were received and stored at the National Public Health Laboratory (NPHL). The Bioline™ HIV 1/2 test was performed following the national testing algorithm with Determine™ HIV 1/2 (first test) and KHB Shanghai HIV1/2 (second test). Meanwhile, the performance of the Bioline™ syphilis test was compared with the Hightop RDT and Treponema pallidum hemagglutination assay (TPHA). The enzyme linked immunosorbent assay (ELISA) was used as the reference assay. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and Cohen’s kappa (κ) value were calculated for each marker against the reference assay within a 95% confidence interval (CI) using Epi-info version 7, MedCalc and QuickCalcs for online statistical analysis. A total of 534 blood samples were tested at the NPHL with 70.97% (379/534) from females and 29.03% (155/534) from males. For HIV diagnosis, the Bioline™ HIV1/2 test had a sensitivity of 99.70% (95% CI: 98.30–99.9), specificity of 98.5% (95% CI: 95.58–99.5), PPV of 99.1% (95% CI: 97.40–99.7), NPV of 99.5% (95% CI: 97.3–99.9), accuracy of 99.1%(95% CI: 97-99.7) and Cohen’s kappa of 98.4%(95% CI:96.7–99.9). For syphilis diagnosis, the Bioline™ test had a sensitivity of 95% (95% CI: 73.7–99.7), specificity of 100% (95% CI: 99.1–100), PPV of 100% (95% CI: 79.1–100), NPV of 99.8% (95% CI: 98.7–100), accuracy of 99.9% (95% CI: 99–100), and Cohen’s kappa of 97.3%(95% CI:92.1–100). The results of this study show that the Abbot Bioline™ HIV/Syphilis Duo RDT has a good performance. Therefore, we suggest that this test could be suitable for use in the diagnosis of HIV and syphilis.