title: Validation study of asthma screening criteria based on subjective symptoms and fractional exhaled nitric oxide.
abstract: BACKGROUND
  In the latest Global Initiative for Asthma guideline, neither sputum eosinophilia nor fractional exhaled nitric oxide (FeNO) have been evaluated prospectively as an aid in asthma diagnosis, but these measurements are being evaluated for potential use in determining optimal treatment.
  
  
  OBJECTIVE
  To report criteria for screening asthma using subjective symptoms and FeNO levels and results of a prospective validation study using these criteria.
  
  
  METHODS
  Sixty-one outpatients with recurrent cough, wheezing, or dyspnea underwent measurements of FeNO levels, pulmonary function, methacholine airway responsiveness, and inflammatory cells in induced sputum. The sensitivity, specificity, and concordance achieved using the FeNO-based criteria (at least 1 of the following subjective symptoms: recurrent cough, wheezing, or dyspnea and/or FeNO level ≥ 40 ppb) were analyzed and compared with the values obtained using conventional asthma diagnostic criteria, which includes subjective symptoms with any 2 of the following conditions: airway hyperresponsiveness, reversible airflow limitation, and eosinophilia in induced sputum.
  
  
  RESULTS
  Of the 61 patients, 41 were diagnosed as having asthma by the conventional criteria, and 33 were diagnosed as having asthma by the FeNO-based criteria, which showed a sensitivity of 78.6%, a specificity of 89.5%, and a concordance rate of 0.62. Nine of 42 patients were misdiagnosed as not having asthma by FeNO-based criteria (mean [SD] FeNO level, 23.9 [8.0] ppb). Seven of 9 patients were diagnosed as having nonatopic asthma according to IgE levels.
  
  
  CONCLUSIONS
  Asthma may be accurately diagnosed in daily practice on the basis of subjective symptoms and FeNO levels, particularly in atopic patients.
authors: Department of Pulmonary Medicine, School of Medicine, Fukushima Medical University, Fukushima City, Japan. fukuhara@fmu.ac.jp
authors: Atsuro
authors: A
authors: Fukuhara
authors: Junpei
authors: J
authors: Saito
authors: Suguru
authors: S
authors: Sato
authors: Yasuko
authors: Y
authors: Sato
authors: Takefumi
authors: T
authors: Nikaido
authors: Kazue
authors: K
authors: Saito
authors: Naoko
authors: N
authors: Fukuhara-Nakagawa
authors: Yayoi
authors: Y
authors: Inokoshi
authors: Taeko
authors: T
authors: Ishii
authors: Yoshinori
authors: Y
authors: Tanino
authors: Takashi
authors: T
authors: Ishida
authors: Mitsuru
authors: M
authors: Munakata
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000175:diagnosis* / Q000276:immunology / Q000378:metabolism; D001944:Breath Tests / Q000379:methods; D001985:Bronchial Provocation Tests; D004802:Eosinophilia / Q000097:blood; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis* / Q000378:metabolism; D011446:Prospective Studies; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D013183:Sputum / Q000166:cytology; D055815:Young Adult
chemical_list: D016210:Methacholine Chloride; D009569:Nitric Oxide; D007073:Immunoglobulin E