Fig. 2
Receiver-operating characteristic (ROC) curve for all patients (n = 232) to determine the optimal cut-off values that best identified sputum eosinophilia ≥ 3% and sputum neutrophilia ≥ 61%. a Optimal cut-off values of blood eosinophil count and FeNO were 0.2 × 109/L (sensitivity: 85%, specificity: 57%, AUC = 0.744, p < 0.001) and 30.25 ppd (sensitivity: 81%, specificity: 49%, AUC = 0.653, p < 0.001). b Optimal cut-off values of blood neutrophil count/proportion were 4.7 × 109/L or 69.3% (sensitivity: 73%, specificity: 61%, AUC = 0.663, p = 0.012; sensitivity: 50%, specificity: 83%, AUC = 0.691, p = 0.003)