A low exhaled nitric oxide level excludes a short-term benefit from inhaled corticosteroids in suspected asthma: A randomized placebo-controlled trial.

Background And Objective: Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker that reflects IL-4/IL-13 production and therefore represents T2 allergic inflammation. FeNO has previously been used to guide inhaled corticosteroid (ICS) treatment in asthma. The purpose of this study was to determine if a low FeNO (≤27 ppb) could be used to reliably identify patients with symptoms suggestive of asthma who would not benefit from initiating treatment with an ICS.