ABSTRACT
<p><b>OBJECTIVE</b>To investigate the value of fractional nitric oxide concentration in exhaled breath (FeNO) in assessing the level of asthma control in children.</p><p><b>METHODS</b>A total of 226 asthmatic children were divided into controlled asthma (n= 86), partially controlled asthma (n=63), and uncontrolled asthma groups (n=77). Ninety healthy children were enrolled as controls. FeNO was measured for both asthmatic and healthy children using the Swedish-designed NIOX system.</p><p><b>RESULTS</b>The control group had an FeNO of 14±6 ppb, the controlled asthma group had an FeNO of 29±26 ppb, the partially controlled asthma group had an FeNO of 32±30 ppb, and the uncontrolled asthma group had an FeNO of 40±32 ppb. The three asthma groups showed significantly higher FeNO than the control group (P<0.05). The uncontrolled asthma group showed significantly higher FeNO than the controlled asthma group (P<0.05), but there were no significant differences in FeNO between the partially controlled and uncontrolled asthma groups and between the partially controlled and controlled asthma groups (P>0.05).</p><p><b>CONCLUSIONS</b>Asthmatic children have significantly higher FeNO than healthy children, and FeNO is correlated with the level of asthma control.</p>