Supplementary Material for: Diagnostic Performance of Endocytoscopy for Esophageal Eosinophilia

<b><i>Introduction:</i></b> Eosinophils in the esophageal epithelium are unevenly distributed in eosinophilic esophagitis (EoE). Esophageal eosinophilia (EE) may be observable by endocytoscopy (EC). This study aimed to evaluate the diagnostic performance of EC for the diagnosis of EE. <b><i>Methods:</i></b> A total of 33 EoE patients underwent EC with methylene blue staining from March 2020 to April 2021. A total of 194 EC images with corresponding biopsies were obtained. Three findings of EC, increased squamous cells (item I), increased inflammatory cells (item II), and cells with bilobed nuclei (item III), were established. These findings were reviewed by two endoscopists to diagnose EE. Another four endoscopists reviewed the images for interobserver agreement. <b><i>Results:</i></b> When all three items were met by EC, the sensitivity and the accuracy for the diagnosis of EE were 88% and 76%, respectively. The integrated diagnostic odds ratios (ORs) for the diagnosis of EE of the four endoscopists were significant (OR: 3.98, 95% CI: 2.94–5.40, <i>p</i> &lt; 0.001). The results were similar when only item III was met. Interobserver agreement was good for item III to diagnose EE (kappa value = 0.653). <b><i>Discussion/Conclusion:</i></b> The diagnostic performance of EC for EE is acceptable and has good interobserver agreement. It may be useful for targeted biopsy in EoE patients.