Optimizing syphilis screening in South Africa: efficacy of the iStatis antibody test in point-of-care settings amid reinfection challenges.

Background: Syphilis poses a significant threat to global health, particularly in high-risk populations and resource-limited settings. Despite progress in HIV screening, syphilis testing often lags, exacerbating disparities in healthcare delivery. This study evaluated the clinical performance of the iStatis Syphilis Antibody (Ab) Test in South African point-of-care environments.

Methods: A prospective cross-sectional study was conducted with 1,500 enrolled participants across three urban South African sites. The clinical performance of the iStatis Syphilis Antibody (Ab) Test was evaluated using three sample types: capillary blood, EDTA venous whole blood, and plasma. Diagnostic sensitivity and specificity were assessed.

Results: The iStatis test demonstrated excellent diagnostic performance, with sensitivities of 96.40% (capillary blood), 98.80% (venous whole blood), and 99.00% (plasma), and a specificity of 100% across all sample types. A high prevalence of syphilis (33%) was identified. Notably, 90.51% of positive cases were female, and 75.7% of these women were pregnant, highlighting a vulnerable population. The study also revealed a high reinfection rate, suggesting that syphilis can recur relatively quickly post-treatment, underscoring the ongoing transmission challenge.

Conclusion: The iStatis Syphilis Antibody Test is a highly accurate and versatile tool that detects syphilis at different stages using various sample types, making it ideal for use in settings without full laboratory access. The study highlights its potential to improve early diagnosis and control of syphilis, especially in light of high reinfection rates in South Africa. Further research is needed to assess its use in rural areas, long-term performance, and cost-effectiveness to support wider adoption.