Infliximab area under the curve (AUC) at (a) week 2 and (b) week 6 was compared for week 14 biochemical outcomes. (c) The week 14 AUC cutoff point associated with week 14 biochemical remission was determined with the Youden index from the receiver operating characteristic curve. Infliximab AUC at (d) week 14 (e) week 26, and (f) week 52 was compared for week 52 biochemical outcomes. AUROC, area under the receiver operating characteristic curve; CI, confidence interval; NPV, negative predictive value; PPV, positive predictive value; Sens., sensitivity; Spec., specificity.