Gastroesophageal reflux disease (GERD) is a common condition affecting more than 100 million adults in the U.S., and it significantly impacts patients' quality of life while imposing billions of dollars of direct and indirect costs each year upon our healthcare system. Current diagnostic tests for GERD are highly invasive and medically inadequate, and the goal of this project is to develop a novel, minimally invasive Mucosal Impedance technique for more accurate detection of GERD while reducing costs.

Inclusion Criteria:

• Patients undergoing standard of care EGD with 48-hr pH testing by BRAVO
• Previous diagnosis of reflux
• At least 18 years of age

Exclusion Criteria:

• Those less than 18 years of age
• Unable to give informed consent
• Use of acid suppressive therapy within the last 10 days
• Known history of Barrett's esophagus, gastric surgery, alcoholism, or significant motility condition