Fig. 2From: The utility of initial procalcitonin and procalcitonin clearance for prediction of bacterial infection and outcome in critically ill patients with autoimmune diseases: a prospective observational studyReceiver operating curve (ROC) analysis on discrimination of bacterial infection. Peak PCT levels within 24 h (PCT peak ) had the better performance for bacterial infection with an AUC of 0.902 and had a sensitivity of 79.6 %, specificity of 89.6 % at the threshold of 0.94 μg/LBack to article page