The ROC curve showed that the area under the ROC curve for the CRP level of necrotic appendicitis was 0.862, and the optimal cutoff value of CRP for surgical indication for classifying cases was around 4.95 mg/dl (sensitivity = 84.3%, specificity = 75.8%, false positive rate = 24.2%, false negative rate = 15.7%, positive predictive value = 64.2%, negative predictive value = 90.4%; figure 1). This evidence concerns the gene CRP and appendicitis.