Comparison of agreement among treponemal testing methods
DOI:
https://doi.org/10.14456/taj.2026.13Keywords:
syphilis, treponemal test, electrochemiluminescence immunoassay, immunochromatographic testAbstract
This study aimed to compare the agreement of Treponema pallidum antibody detection between electrochemiluminescence immunoassay (ECLIA) and immunochromatographic test (ICT), using TPHA as the reference treponemal test. A total of 204 serum samples were re-evaluated using a treponemal testing algorithm, beginning with TPHA followed by RPR. The positive percentage agreement (PPA) values were 97.78% and 78.13%, respectively. The negative percentage agreement (NPA) was 100% for both methods, and the overall percentage agreement (OPA) values were 99.41% and 95.60%, respectively. The kappa coefficients indicated almost perfect agreement (kappa = 0.99, 0.86, respectively. From a clinical significance perspective, the results demonstrated that ECLIA showed a higher degree of agreement with TPHA than ICT among the pre-selected samples. Furthermore, treponemal tests demonstrated high diagnostic performance, with high sensitivity and specificity. They can detect latent infection and cases with a history of prior treatment. ECLIA provides high sensitivity and specificity and yields quantitative results, making it appropriate for laboratories requiring high analytical accuracy, despite its higher cost and instrument requirements. In contrast, ICT as a rapid test provides rapid results, ease of use, and lower cost, making it suitable for initial screening in resource-limited settings. However, ICT has lower sensitivity and specificity and cannot be used to monitor antibody levels. Therefore, using ICT for preliminary screening in combination with ECLIA for confirmation may enhance overall diagnostic effectiveness and suit the context of healthcare services at different levels.
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