Background and Aims Asthma is a chronic inflammatory disease of the lower airways, whose treatment is conducted by guidelines in use, depending on clinical markers of disease control (ACT=asthma control test score) and spirometric values. Due to situations in which there is discrepancy between the two categories of parameters, we aimed this study to examine whether FENO measurement may be an additional argument in guiding the treatment.

Method The prospective study lasted five months and included 30 patients diagnosed as moderate persistent asthma, aged 5–17 years, nonsmokers; ACT score, FEV1 and FENO were assessed.

Results 12 patients had ACT> 19, normal FEV1 values and FENO < 20ppb.

18 patients had ACT < 19; 9 of them had normal FEV1 values and 16 had FENO values> 32ppb.

Conclusion FENO value correlates better than FEV1 with clinical asthma control score, so it can be an additional marker in therapeutic decision.