24 hour Ambulatory combined pH (acid)and impedance Monitoring- Ambulatory combined pH and impedance monitoring, called the Sleuth System is the new gold standard for objectively assessing nonacid as well acid reflux activity and can confirm significant gastroesophageal reflux disease. Studies show that patients with persistent symptoms on medical therapy have nonacid reflux 40% of the time. pH and impedance reflux monitoring is usually performed prior to any antireflux procedure and is used to diagnose difficult or atypical reflux cases. A tiny tube is placed through the nose and into the esophagus (food tube) above the lower esophageal sphincter. The test runs for 24 hours and measures the number of times acid enters the esophagus. Wireless technology called The BRAVO System is also available. Click here to learn more about BRAVO. BRAVO is a wireless transmitting capsule which is placed usually following endoscopy. It will measure acid reflux activity only for 48 hours and the capsule will usually fall off within 3 to 5 days and is passed. Bravo offers longer data collection times and better patient comfort, but is limited in that it only measures acid reflux activity and will not measure nonacid reflux. The newer Sleuth and Zephyr pH-impedance reflux testing that measures nonacid and acid reflux is available through Greenwich Village Gastroenterology.