FIG 3.

Distribution of the P/N ratios of four groups of archived human patient sera and determination of the optimal cutoff P/N value of ZIKV-VLP-MAC-ELISA from acute-phase (left panel) and convalescent-phase (right panel) sera. (A) P/N ratios for ZIKV, WNV, DENV, and other serum specimens. (B) Plot of sensitivity versus 100−specificity (%) based on P/N values from a panel of 42 ZIKV-confirmed sera and 173 control sera. (C) Optimal cutoff value was determined by the magnitude of likelihood ratio positive (LR+) calculated by dividing the sensitivity by 1−specificity.