Diagnostic performance of the Hightop Rapid Diagnostic Test for the detection of anti- Treponema pallidum antibodies in Cameroon: a laboratory-based cross-sectional and comparative study

Abstract

OBJECTIVE: The study was conducted to assess the diagnostic performance of the Hightop Syphilis Rapid Diagnostic Test (RDT) in comparison with the ELISA test used as a reference method. DESIGN: A laboratory-based cross-sectional and comparative study was conducted to assess the diagnostic performance of the Hightop Syphilis RDT. SETTING: Blood samples obtained from adult participants in eight health facilities were analysed at the National Public Health Laboratory (NPHL), Ministry of Public Health, Yaounde, Cameroon. PARTICIPANTS: From 29 April to 25 August 2023, 583 adult participants of both sexes (aged ≥21 years), including both syphilis positive and syphilis negative, were recruited consecutively in eight health facilities in eight regions of Cameroon. OUTCOME MEASURES: antibodies using the One Step Rapid Test (Qingdao Hightop Biotech), a non-treponemal test and ELISA (Biorex Diagnostics, UK), a treponemal test used as a reference method. Diagnostic performance of the Syphilis RDT was analysed using Epi Info V.7 and validated through online statistical tools such as StatPages, GraphPad, QuickCalcs and MedCalc software. RESULTS: Of the 583 samples tested, the Hightop Syphilis RDT revealed a sensitivity of 84.6% (95% CI: 74.8% to 91.1%) and specificity of 98.5% (95% CI: 97.5% to 99.1%). The positive predictive value (PPV) and negative predictive value (NPV) were 84.6% (95% CI: 74.8% to 91.1%) and 98.5% (95% CI: 97.5% to 99.1%), respectively. Regarding the stratification of diagnostic performance by clinical stage, the test showed a sensitivity of 100.0% (95% CI: 71.51% to 100.0%) and specificity of 99.06% (95% CI: 94.86% to 99.98%). The PPV and NPV were 91.67% (95% CI: 61.00% to 98.72%) and 100.0% (95% CI: 96.55% to 100.0%), respectively, in symptomatic individuals. Among asymptomatic individuals, sensitivity was 97.56% (95% CI: 87.14% to 99.94%) and specificity was 100.0% (95% CI: 99.14% to 100.0%). The PPV and NPV were 100.0% (95% CI: 91.19% to 100.0%) and 99.77% (95% CI: 98.40% to 99.97%), respectively. CONCLUSIONS: The Hightop Syphilis RDT demonstrated adequate diagnostic performance, particularly among symptomatic individuals, supporting its utility as a reliable tool for syphilis detection in clinical settings.