Fig. 2From: Clinical and pulmonary function changes in cough variant asthma with small airway diseaseFEF50% and FEF25–75% as early markers of small airway disease. a Representative spirometry results in our cohort are showed. Normal airway is the group CVA with normal FEF50%. Small airway disease is the group CVA with lower FEF50%. b Diagnostic test of FEF50%. FEF25–75% is defined as gold standard and FEF25–75% < 70% predicted is set as cut value. The sensitivity, specificity and accuracy of new measurement (FEF50%) are measured. c The average value of FEF50% and FEF25–75% (p > 0.05). The linear correlation analysis of FEF50% and FEF25–75% in CVA patients. All spirometries were performed by well-trained technician with all data repeated three timesBack to article page