title: Diagnostic accuracy of fractional exhaled nitric oxide in asthma: a systematic review and meta-analysis of prospective studies.
abstract: BACKGROUND
  Fractional exhaled nitric oxide (FeNO) has been proposed as a non-invasive measure of airway inflammation in asthma. However, its accuracy for the diagnosis of asthma in different populations is not completely clear. The aim of this study was to investigate the accuracy of FeNO measurement for the diagnosis of asthma through a systematic review and meta-analysis of prospective studies.
  
  
  METHODS
  A systematic search current to July 2014 was performed in Pubmed, EMBASE, Medline, the Cochrane databases, CNKI, Wanfang and Weipu to find relevant studies. All prospective studies on the use of FeNO for the diagnosis of asthma were included.
  
  
  RESULTS
  Twenty-five studies including 3983 subjects were analyzed. The pooled sensitivity, specificity and diagnostic odds ratio (DOR) for the entire population was 72% (95% CI, 70-74%), 78% (95% CI, 76-80%) and 15.92 (95% CI, 10.70-23.68), respectively. The area under the summary receiver operating characteristic (sROC) curves revealed a receiver-operating characteristic of 0.88. In subgroup analysis, the DOR for patients using corticosteroids, as well as those for steroid-naïve, non-smoking, smoking, chronic cough and allergic rhinitis patients were 4.47 (95% CI, 3.39-5.90), 21.40 (95% CI, 15.38-29.76), 19.84 (95% CI, 15.63-25.19), 5.41 (95% CI, 2.97-9.86), 35.36 (95% CI, 23.90-52.29), and 2.99 (95% CI, 0.85-10.45), respectively.
  
  
  CONCLUSIONS
  FeNO is accurate for the diagnosis of asthma in steroid-naive or non-smoking patients, particularly in chronic cough patients.
authors.affiliation: a Department of Pulmonary Diseases , Jinan Military General Hospital , Jinan , Shandong , China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Guo
authors.affiliation: a Department of Pulmonary Diseases , Jinan Military General Hospital , Jinan , Shandong , China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: a Department of Pulmonary Diseases , Jinan Military General Hospital , Jinan , Shandong , China.
authors.forename: Guohong
authors.initials: G
authors.lastname: Xing
authors.affiliation: a Department of Pulmonary Diseases , Jinan Military General Hospital , Jinan , Shandong , China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
mesh_terms: D001249:Asthma / Q000175:diagnosis*; D001944:Breath Tests; D045853:Exhalation; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D011446:Prospective Studies; D015203:Reproducibility of Results
chemical_list: D009569:Nitric Oxide
keywords: FeNO; asthma; diagnostic accuracy; diagnostic odds ratio; meta-analysis