The probe continuously measures the amount of acid in the esophagus and transmits the information to a small electronic device about the size of a cell phone, which is worn on the patient's belt. After 2 days the data from the monitor is downloaded to a computer for analysis. For the test to be accurate the patient must remain off all acid suppressing medication, like PPIs and H2-Blockers, for 7 days prior to beginning the study. It is okay to use antacids like Rolaids® and Tums® to control acid symptoms during the pre-testing time, but even these medication need to be avoided during the 48 hours of the actual test.
The Bravo Probe is completely disposable and releases from the lining of the esophagus after about 7 to 10 days. It will pass through the intestinal tract and out of the body during a normal bowel movement. While the probe is in place, some patients experience slight discomfort with swallowing, but this is temporary and generally does not require any alteration in diet.
The results of the test are analyzed and compared to what is expected normally. Each patient receives a score, called the DeMeester score, which takes into consideration the number of times abnormal amounts of acid were present in the esophagus, and how long they remained. This test is considered one of the most definitive studies to confirm the diagnosis of acid reflux. If the pH study is normal, it does not mean the patient doesn't have reflux, it simply means that acid is not likely the cause of their symptoms.
When Acid Reflux is suspected but not confirmed, it may be necessary to actually measure the amount of acid in the esophagus over a 24-48 hour period to confirm the diagnosis of GERD. Traditionally, this was accomplished by placing a tube down through the nose into the esophagus, which was connected to a monitoring device. Today, that rather uncomfortable procedure has been replaced by a less cumbersome process where a tiny capsule, called a Bravo Probe, is attached during an endoscopy directly to the lining of the esophagus.