In the latest Global Initiative for Asthma (GINA) guideline, fractional exhaled nitric oxide (FeNO) was not evaluated for asthma diagnosis.
This Japanese study included 61 outpatients with recurrent cough, wheezing, or dyspnea (subjective symptoms for asthma).
The cutoff FeNO level was ≥40 ppb.
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 79%, a specificity of 89%. The concordance rate was 0.62.
9 of 42 patients were misdiagnosed as not having asthma by FeNO-based criteria (in that group the mean FeNO level was 24 ppb).
The authors concluded that asthma may be accurately diagnosed in daily practice on the basis of subjective symptoms and FeNO levels, particularly in atopic patients.
Video by the manufacturer of the FENO measurement device Niox Mino, Aerocrine:
Validation study of asthma screening criteria based on subjective symptoms and fractional exhaled nitric oxide. Annals of Allergy, Asthma & Immunology, Volume 107, Issue 6 , Pages 480-486, December 2011.
ATS Guideline on Exhaled Nitric Oxide Levels (FENO) Use
Image source: NioxMino.
Comments from Twitter:
Andrew Nickels @EthicalAllergy: What age group do you trust FeNO? I have seen recently that FeNO is not a reliable marking in elderly.