Comparison of “Lumipulse anti‐Treponema pallidum” and “Architect Syphilis TP” and further examination

BACKGROUND: Syphilis is a sexually transmitted disease caused by Treponema pallidum (TP) infection. In recent years, diagnostic reagents with fully automated immunoassay instruments have become mainstream. However, these positive screening tests with high sensitivity, which are performed with full automation, need confirmation by Treponema pallidum particle agglutination (TPPA) to be judged as positive. METHODS: We evaluated the diagnostic performance of Lumipulse G TP‐N assay (Lumi‐TP, Fujirebio Inc) in 223 preselected TP‐positive samples and 1041 TP‐negative samples, compared it with that of the TP gold standard test (TPPA) and Architect Syphilis TP test (Archi‐TP, Abbott). RESULTS: The concordance rates for the results for the positive and negative samples between Lumi‐TP and TPPA were 100%. On the other hand, the rates for the results between Archi‐TP and TPPA were 100% for positive samples and 99.14% (1032/1041) for negative samples. Correlation tendency and rate between Archi‐TP and Lumi‐TP were 2.549 and 0.841 in positive specimens up to 160 detected values in Lumi‐TP. However, the detection value of Archi‐TP reached a plateau when it exceeded about 40. Furthermore, according to the comparison of each value obtained from Archi‐TP and Lumi‐TP with the strength of the staining of each line in the immune‐chromatography assay kit, ESPLINE TP (Fujirebio Inc) for TP major antigens, Tp15‐17 and TpN47, it was found that Lumi‐TP obtained higher values than Archi‐TP, particularly for TpN 47. CONCLUSIONS: Lumi‐TP has high specificity and is useful not only for screening but also for determining the amount of anti‐TP antibodies.