Validity criteria and comparison of analytical methods of flow-independent exhaled NO parameters

Respir Physiol Neurobiol. 2006 Sep 28;153(2):148-56. doi: 10.1016/j.resp.2005.10.005. Epub 2005 Nov 23.


The objective was to assess both validity and comparability of multiple constant (MCF, mainly performed) and dynamically changing (DCF, new method) flow analyses calculating alveolar concentration (Calv(NO)), maximum conducting airway flux (J'aw(NO)) and airway diffusing capacity (Daw(NO)) of exhaled NO (FE(NO)). (Calv(NO), J'aw(NO))(R) where R is the correlation coefficient of the linear regression between NO output and expiratory flow rate (MCF) and (Calv(NO), J'aw(NO), Daw(NO))(Delta100) where Delta100 is the ratio ([observed-predicted FE(NO)]/observed FE(NO)) at 100 ml/s (DCF) were assessed in 18 healthy subjects (10 atopic). MCF demonstrated a linear relationship (R > or = 0.80) between NO output and expiratory flow in 15/18 subjects. DCF was valid (Delta100 < or = 30%) in 12/18 subjects. A good agreement between MCF and DCF was evidenced in the nine subjects with R > or = 0.80 and Delta100 < or = 30%. Failure of validity criteria was mainly observed in atopic subjects. In conclusion, when validity criteria are satisfied, the new DCF method similarly characterizes NO exchange parameters than MCF approach.

Publication types

  • Comparative Study
  • Validation Study

MeSH terms

  • Adult
  • Algorithms
  • Breath Tests / methods
  • Female
  • Humans
  • Lung / metabolism*
  • Male
  • Middle Aged
  • Models, Biological*
  • Nitric Oxide / analysis*
  • Nitric Oxide / metabolism
  • Pulmonary Gas Exchange / physiology*
  • Pulmonary Ventilation / physiology*
  • Reference Values
  • Reproducibility of Results
  • Respiratory Function Tests / methods
  • Spirometry


  • Nitric Oxide