Ambulatory pH analysis and manometry

Normal esophageal pH is considered to be pH 5.0 to pH 7.0. The esophageal pH value of a severe GERD patient can be lower than 4.0. An ambulatory pH-monitoring device is usually used for continuous measurement of patients’ esophageal pH value for up to 96 hours. A patient is diagnosed with severe GERD when his/her ambulatory esophageal pH value is mostly below 4.0 during the pH study