24-hour pH impedance testing is used to evaluate acid and nonacid reflux from your stomach into your esophagus over the course of a day.
What is 24-hour impedance with manometry?
Twenty-four-hour pH/Impedance monitoring test determines whether there may be an abnormal amount of acid, as well as non-acid reflux (bile, air, etc.) or stomach contents coming back up into the esophagus from the stomach