To evaluate the sensitivity and specificity obtained when using serum levels of PCT and sCD14-ST to distinguish PI versus PN, we performed receiver operating characteristic (ROC) curve analysis of the variations of serum levels of PCT and sCD14-ST in PI and PN cases and calculated the area under the ROC curve (AUC) and the optimal cutoff values (Fig. 2, Table 4). This evidence concerns the gene CALCA and poikiloderma with neutropenia.