In a prospective clinical study with 82 children and adolescents (44 males) with corticosteroid-treated allergic rhinitis and/or asthma, several techniques for measurement of fractional exhaled nitric oxide (FENO) were compared. In agreement with the published guidelines, different techniques and evaluation methods were used in younger (4.9-11.8yr,N=36)and older children (12.2-18.7yr,N=46), respectively.
Chemiluminiscence measurement using the tidal breathing technique gave 3 to 4-fold lower FENO values compared to single exhalation but the results of both techniques were highly correlated.