CALCA and infection: The ROC curve analysis in Fig. 1 for predicting presence of infection demonstrated an AUC of 0.79 for PCT, a best cut-off at 0.25 ng/mL, and a sensitivity of 63.6%, specificity of 83.2%, positive predictive value (PPV) of 79.1%, negative predictive value (NPV) of 69.5%, positive likelihood ratio (LR+) 3.78, negative likelihood (LR-) 0.44, diagnostic odds ratio (DOR) 8.6 (95% CI, P-value <0.001).