Repeated Measurement of Fractional Exhaled Nitric Oxide Is Not Essential for Asthma Screening

Older guidelines recommend that fractional exhaled nitric oxide (FeNO) should be checked more than twice during the same session to confirm an asthma diagnosis. Recent studies show the excellent reproducibility of FeNO measurements. Objetive: We aimed to determine whether repeated FeNO measurements during the same session are necessary for asthma screening. We retrospectively reviewed the electronic medical records of adult outpatients who visited the respiratory medicine department for diagnosis of asthma and assessed FeNO measurements obtained from June 2016 to July 2017. Of the 132 patients enrolled, 79 (59.8%) were diagnosed with asthma. Repeated FeNO measurements taken during the same session showed high reproducibility (intraclass correlation coefficient >0.9; P0.9; P