Figure 1. ROC curve for EBNA1 IgA marker (Δ=1.04).
An optimized threshold value for a given anti-EBV IgA marker was defined as the value on the ROC curve with the highest specificity that successfully identified at least 80% of incident NPC cases (80% sensitivity) in this high-risk population. The alternative threshold had the highest specificity while identifying at least 90% of incident NPC.