Enhancing public health syphilis screening program: a comparative analysis between four different immunoassays

BackgroundSyphilis remains a significant global public health concern, contributing substantially to morbidity and mortality. Given syphilis asymptomatic nature, varied clinical presentations, and severe untreated complications, accurate diagnostic methods are crucial. AimThis study aims to evaluate the performance of the new treponemal test, MAGLUMI-X3(R) Ab-syphilis assay (Maglumi-TP) from Snibe Diagnostics, China, as a potential sensitive, specific TP-Ab-screening & confirmatory method by comparing its performance to the (i) well-established and FDA-approved Abbott ARCHITECT Syphilis-TP (Architect-TP) assay and (ii) Fujiribio INNO-LIA(R) Syphilis Score (INNO-LIA-TP) line-immunoassay. In addition, to evaluate the false positive rate of the RPR non-treponemal test. In this study, we proposed Architect-TP and INNO-LIA-TP as reference assays. MethodWe selected 180 samples that demonstrated agreement and discrepancies between the RPR and Architect-TP. This selection comprised 40 cases (RPR-TP + Architect-TP +), 40 cases (RPR-TP + Architect-TP -), and 100 cases (RPR-TP - Architect-TP -). All selected samples underwent re-testing using the Maglumi-TP and the INNO-LIA-TP assays. ResultsMaglumi-TP demonstrated excellent sensitivity and specificity of 100%, with perfect agreement ({kappa}= 1.00) with Architect-TP. Similarly, Maglumi-TP exhibited excellent sensitivity of 100% (95% CI: 91-100), specificity of 100% (95% CI: 97.4-100), and perfect agreement ({kappa}= 1.00) with the INNO-LIA-TP. Notably, 40 cases (28.8%; 40/139) exhibited false-positive results when using the RPR test compared to the INNO-LIA-TP, indicating a substantial false-positive rate associated with the RPR assay. ConclusionWith its high sensitivity and absence of false-positive and false-negative results, Maglumi-TP emerges as a promising automated screening assay for detecting and confirming TP antibodies.