FIG 2.

ROC analysis to predict truly positive (TP-PA-confirmed) specimens. Signal/cutoff (S/CO) and index values providing 100% specificity were selected for the Architect Syphilis TP assay (manufacturer's reactive S/CO, ≥1.00) (A) and Liaison Treponema assay (manufacturer's equivocal index, 0.90 < 1.10, and positive index, ≥1.10) (B) for which all specimens with higher values resulted in reactive TP-PA results. P was 0.0001 (A) and P was 0.005 (B) by Fisher's exact test. AUC, area under the curve.