gastroesophageal reflux disease (GERD) is a complex disease with heterogeneous symptoms and various pathogenic mechanisms. Esophageal mucosal impedance is a sign of reflux. Impaired esophageal mucosal integrity plays a role in the development of GERD symptoms. It can be used to diagnose the effect of reflux on esophageal mucosa in GERD patients. The measurement of esophageal baseline impedance using multi-channel intraluminal impedance pH test is considered to be an alternative technique for the study of esophageal mucosal integrity, which helps to differentiate GERD from Non-GERD related conditions. Endoscopic guided mucosal impedance test (EMT) is a new technique that uses an open-ended catheter to contact the inner wall of the esophagus to determine the changes in epithelial cells caused by chronic gastroduodenal contents. This test essentially measures the ability of esophageal epithelial cells to conduct electricity. In patients with chronic GERD, esophageal epithelial cell changes, enlarged intercellular space and long-term moist state lead to high electrical conductivity and low mucosal impedance. Real time measurement of mucosal impedance and mucosal admittance guided by endoscopy may help to estimate mucosal integrity and may be a useful diagnostic tool for GERD patients in a manner similar to 24-hour esophageal multichannel impedance pH monitoring.