Preoperative presepsin and C-statistic to predict mortality. Box-and-whisker plot with the tenth and ninetieth percentiles. Solid line inside box = median values of presepsin; plus symbol = mean values of presepsin; blue solid line inside box = optimal threshold. Receiver operating characteristic curves were constructed to evaluate the predictive power of presepsin for 30-day, 6-month, and 2-yr mortality. The Youden Index was used to calculate optimal threshold for presepsin in prediction of 30-day, 6-month, and 2-yr mortality. Samples were taken in the afternoon the day before surgery.