Esophageal manometry is a test that measures the function of the esophagus and the characteristics of the valve between your esophagus and the stomach. The test provides information that assists the doctor in the diagnosis of patients with swallowing difficulties and gastroesophageal reflux disease. Esophageal manometry is also used for evaluation prior to surgery. A small, very flexible catheter will be gently inserted through the nose into the esophagus. This catheter is attached to a machine that records and analyzes pressure measurements from sensors on the catheter. This information helps your doctor to diagnose your illness and plan the best treatment for you.