RESULTS: The proportion of increased FeNO value in NAR and AR was 15.6% and 35.2%, respectively. The prevalence of sputum eosinophilia was significantly higher in increased FeNO group than that in normal FeNO group in AR (59.42% Vs 12.60%, P<0.01), but was similar between increased FeNO group than that in normal FeNO group in NAR (7.1% Vs 10.5%, P=0.754). FeNO value was positively related to sputum eosinophils in AR (r=0.376, P<0.01). Increase FeNO was closely related to sputum eosinophilia (r=0.503, P<0.01). FeNO value >25.5ppb was a cutoff value to identify eosinophilic inflammation in the airway with sensitivity of 73.2% and specificity of 80%, ROC=0.787. While FeNO value was irrelevant to sputum eosinophils in NAR (r=0.096, P=0.379).