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pH Probe Studies


A pH probe is a test used to test for the amount and seriousness of acid reflux, or stomach acids that back up into the esophagus. A small flexible tube will be passed through one of your nostrils and placed into position in the esophagus. 

What to expect

During this outpatient procedure, an extremely thin tube will be passed through the nose and into the esophagus. The tube will make you feel as if you are going to gag or cough or even sneeze when inserted. An X-ray may be performed to make sure the probe is in the right place. This tube will be connected to a small monitor that will record your acid levels over the course of a 24-hour period. You will leave the office and go back to your daily routine and return 24 hours later to have the tube removed. 

What can be found?

A pH probe study can help doctors determine if there is acid reflux, or GERD, as well as how serious the condition is. 

How to prepare

Prior to having the tube inserted, you will be asked to restrict food and drink, so be sure to follow your doctor’s instructions. A list of medicines will also be off limits in order to reduce the amount of acid produced by the stomach. The doctor will also ask you to keep a diary of your activity and food intake during the course of the procedure.