呼出气一氧化氮检测诊断支气管哮喘

Fractional exhaled nitric oxide in diagnosis of bronchial asthma

目的评价呼出气一氧化氮（fractionalexhalednitricoxide，FeNO）检测诊断哮喘的准确性及其最佳界值。方法使用FeNO测试仪（NIOXMINOAerocrineAB瑞典）对109例疑诊哮喘患者进行FeNO浓度测定，以哮喘的常规诊断方法为参照。不同的FeNO界值对应不同的敏感度和特异度，绘制ROC曲线，评价FeNO诊断哮喘的准确性并得出最佳界值。结果109例患者中，47例最终被诊断为哮喘，62例非哮喘患者。哮喘组FeNO中位数（四分位数间距）明显高于非哮喘组：70ppb（87ppb）比16ppb（21ppb），P〈O．001。ROC曲线下面积为0．808（95％置信区间：0．719～O．896），FeNO诊断哮喘的最佳界值为41ppb，以41ppb为标准诊断哮喘的敏感度为68．1％，特异度为83．9％，阳性预测值为76．2％，阴性预测值为77．6％，准确度为77．1％。结论FeNO诊断哮喘的敏感性和特异性是可接受的，可以被用作哮喘诊断的辅助工具。

Objective To assess the accuracy of exhaled nitric oxide for the diagnosis of bronchial asthma （asthma） and to determine the optimal cutoff value. Methods 109 patients received a FeNO test by nitric oxide analyzer （NIOX MINO, Aerocrine AB, Solna, Sweden）, referenced the conventional diagnostic methods of asthma. Different FeNO measurements corresponds to different degrees of sensitivity and specificity. The accuracy of FeNO was assessed and the optimal cutoff value of FeNO was determined by the means of the receiver operating characteristic （ROC） curves. Results A total of 109 patients were enrolled, in which 47 cases were diagnosed as asthma, and in which 62 cases were diagnosed as non-asthmatics. The asthma group FeNO median （interquartile range） was significantly higher than the non-asthmatic group=70 ppb （87 ppb） vs 16 ppb （21 ppb）, P d0. 001. The area under the ROC curve was 0. 808 （95% CI ：0. 719 to 0. 896, P d0. 001）. The optimal FeNO cutoff value was 41 ppb with a sensitivity of 68.1% ,a specificity of 83.9%, a positive predictive value of 76.2%o, a negative predictive value of 77.6% and an accuracy of 77.1%. Conclusions FeNO can be used as an additional diagnostic tool for the screening of patients with a suspected diagnosis of asthma.