Portable exhaled nitric oxide as a screening tool for asthma in young adults during pollen season

Chest. 2008 Apr;133(4):906-13. doi: 10.1378/chest.07-1561. Epub 2007 Oct 20.


Background: The fraction of exhaled NO (FeNO) is valuable for the follow-up of asthmatic patients. However, its usefulness as a screening tool for asthma is not established.

Methods: We screened a population of 961 university students with a modified European Community Respiratory Health Survey questionnaire that has been previously used for the screening of respiratory symptoms related to asthma. All subjects with a positive answer to at least one question (n = 149) were submitted to FeNO measurement with a portable nitric oxide analyzer. Subsequently, they were submitted to spirometry and evaluated by a physician blinded to FeNO measurements. Seventy students with no respiratory symptoms served as control subjects.

Results: Asthma was diagnosed in 63 subjects, and allergic rhinitis was diagnosed in 57 subjects. Asthmatics presented higher FeNO values than control subjects (median, 20 parts per billion [ppb]; interquartile range, 14 to 31 ppb; vs median, 11 ppb; interquartile range, 7 to 13 ppb, respectively; p < 0.0001), whereas they did not differ from patients with allergic rhinitis (median, 17 ppb; interquartile range, 12 to 23 ppb; p = 0.28). FeNO values > 19 ppb presented 85.2% specificity and 52.4% sensitivity for the diagnosis of asthma (area under the curve [AUC], 0.723). The diagnostic performance of FeNO was better in nonsmokers (AUC, 0.805), yet FeNO values > 25 ppb were characterized by specificity > 90% for the diagnosis of asthma both in smokers and in nonsmokers. However, FeNO was not a good marker for the differentiation between asthma and allergic rhinitis.

Conclusions: FeNO measurement with a portable analyzer is useful for the screening for asthma in young adults. Significant confounding factors are allergic rhinitis and current smoking.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Asthma / diagnosis*
  • Asthma / etiology
  • Asthma / metabolism*
  • Biomarkers / metabolism
  • Breath Tests / instrumentation
  • Diagnostic Equipment / trends
  • Female
  • Humans
  • Lung / metabolism*
  • Male
  • Mass Screening / instrumentation
  • Mass Screening / methods*
  • Nitric Oxide / metabolism*
  • Predictive Value of Tests
  • Reproducibility of Results
  • Rhinitis, Allergic, Seasonal / complications
  • Seasons
  • Sensitivity and Specificity
  • Smoking / adverse effects
  • Spirometry / instrumentation*


  • Biomarkers
  • Nitric Oxide