Sensitivity and specificity of various biomarkers and scoring systems in predicting ICU mortality. Shown are ROC plot analyses of the abilities of various biomarkers to predict outcome (for example ICU mortality) in sepsis. Patients are grouped into (a) those with a clinical diagnosis of sepsis based on international guidelines and (b) those with circulating PCT levels above 1 ng/ml. Sensitivity was calculated with patients who died during their ICU stay and specificity was calculated with ICU survivors. The areas under the ROC curve are given with 95% confidence intervals. ICU, intensive care unit; PCT, procalcitonin; ROC, receiver operating characteristic.