Identifying the predictive value of fractional exhaled nitric oxide (FeNO) for uncontrolled asthma in 3-7-year-old Thai children.

Background: Fractional exhaled nitric oxide (FeNO) is the method for monitoring airway inflammation. However, a singular FeNO value cutoff may not adequately represent the control status across different ages and demographics. This study aimed to evaluate the correlation between FeNO values and asthma control levels, identifying an optimal cutoff point for children aged 3 to 7 years.