A Minimally Invasive Sinonasal Swab Sampling Method and Eosinophil Peroxidase Activity Assay Accurately Predicts Tissue Eosinophilia in Chronic Rhinosinusitis

A definitive diagnosis of eosinophilic chronic rhinosinusitis (eCRS) requires invasive surgical tissue sampling and histologic enumeration of intact eosinophils. There are no minimally invasive methods to identify tissue eosinophilia among patients with eCRS. Prior investigations have reported eosinophil peroxidase (EPX) to be an accurate biomarker of tissue eosinophilia. The objective of this study was to develop a minimally invasive and rapid method that utilizes a nasal swab and a colorimetric EPX activity assay to predict tissue eosinophilia in eCRS.