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Bravo Capsule pH Test 

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The multidisciplinary team of esophageal experts at the Houston Methodist Lynda K. and David M. Underwood Center for Digestive Disorders wants you to eat, drink and live the healthy life you deserve. We get you in and out to test and relieve the acid-induced pain in your throat.


The Bravo capsule pH test is a battery-powered device that measures and transmits the amount of acid in your esophagus. The esophagus, or gullet, is the “tube” that connects your throat to your stomach. With continuous exposure, the acid causes inflammation, pain and the potential for permanent damage.


Stomach acid is not meant for the esophagus. After you eat or drink, the food and liquid meet a valve called the lower esophageal sphincter (LES). The LES senses the movement of food down the tube, opens it to let the contents pass into the stomach and then closes. Unfortunately, the acid moves from the stomach back up the tube when your LES is loose or opens at the wrong time. We perform the pH test to evaluate the degree of acid exposure in the esophagus. This helps us develop a plan to treat the underlying problem, whether it is uncontrolled heartburn leading to weight loss and dehydration or unrelenting chest pain despite the use of acid blockers.

Top-Rated Gastrointestinal (GI) Surgeons

Our gastroenterology team at the Underwood Center will evaluate your acid exposure using the Bravo capsule pH system. Bravo is the first system that monitors the acidity of the esophagus without a catheter (thin tube). This test eliminates the discomfort of a catheter during the test period. You can eat and engage in normal activities, which improves the quality of the test results.


Once attached, the capsule test rates the acidity in your esophagus for 48 to 96 hours. We choose the capsule’s location with an upper endoscopy or through the mouth with a specialized delivery system.


Specialists at the center offer personalized care and treatment plans for patients who need experienced esophageal care. U.S. News & World Report ranks Houston Methodist Hospital No. 1 in Texas and 5th in the nation for Gastroenterology & GI Surgery. Our team has decades of experience in the diagnosis and treatment of digestive disorders.

Before, During & After the Test

How do I prepare for the Bravo capsule pH test?

Do not eat or drink after midnight prior to your test. Do not smoke the day of your test. If you’re an asthma patient, carry your inhaler.


Follow your physician’s instructions and discontinue the recommended medications seven days before the procedure. Drugs such as proton pump inhibitors (AcipHex®, Prilosec®, Prevacid®, Protonix®, Nexium®, Zegerid®, Dexilant®) or H2 blockers (Axid®, Pepcid®, Tagamet®, Zantac®) may affect test results. If your physician instructs you to withhold these medications, but you experience discomfort, you may take these or similar antacids: Rolaids®, Tums® or Mylanta®.


Other considerations include:

  • Patients with a pacemaker or implantable cardiac defibrillator should not undergo a Bravo pH capsule test.
  • Some patients may experience mild chest pain.
  • The Bravo pH capsule contains a small magnet. You should not have an MRI for 30 days after the test.

What should I expect on the day of the test?

We admit you as an outpatient, and a staff member takes your vital signs. A doctor follows up with the steps below:

  1. We attach a gel cap-sized device — the Bravo capsule — into the inner layer of the esophagus via a delivery system.
  2. After insertion, the doctor releases and removes the delivery system. The device stays in place. The capsule contains a transmitter that sends pH readings via telemetry to a data-capture device worn on your belt.
  3. We give you a diary to document the times when you have reflux symptoms (heartburn, regurgitation, chest pain) with a meal or when you are flat on your back.

What happens after the test?

Once the test is complete, return the diary and Bravo receiver. Our staff will upload the information to a computer for analysis. You may drive yourself home after the test. The capsule passes through the digestive tract and out of your body in about 5-7 days.