Tests for Acid Reflux Disease (GERD)
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World-Class Gastrointestinal (GI) Surgeons
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.
Our gastroenterologists have decades of experience in the diagnosis and treatment of digestive disorders and offer advanced tests and treatments to help you gain relief sooner from acid reflux conditions.
Impedance pH Test for Acid Reflux (GERD)
The 24-hour impedance pH (nasal catheter) probe test monitors acid and non-acid reflux activity. This outpatient procedure allows esophageal specialists at the Underwood Center to evaluate how often stomach acid moves into the esophagus during a 24-hour period.
The test is most often prescribed for patients diagnosed with gastroesophageal reflux disease (GERD) who are not finding relief from acid-suppressive therapy such as proton-pump inhibitors (PPI). Your doctor may administer this test before prescribing acid reflux surgery.
Before, During and After the Impedance pH Test
How do I prepare for the impedance 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®.
Some patients may experience a nosebleed. You may drive yourself home after the procedure.
What should I expect during and after the Impedance pH test?
Testing steps:
- You are admitted as an outpatient, where staff will take your vital signs.
- Once the procedure begins, an esophageal motility test is administered to pinpoint the correct placement of the impedance pH probe. This involves inserting a very small catheter into the nostril and advancing it into the stomach.
- Your doctor slowly withdraws the catheter as you take sips of water. This portion of the test takes 20 to 25 minutes. After that the motility catheter is removed.
- Next your doctor inserts a different catheter, called an impedance pH probe, into the nostril and advances it into the esophagus. The impedance pH probe remains in place for 24 hours. The probe is connected to a small recorder you carry on a strap over your shoulder.
- Before you leave, we will give you information regarding diet, medications, smoking and bathing. We will also give you a diary sheet to record selected events throughout the 24-hour period. You will return the following day to have the probe removed.
- While the impedance pH probe is in place, some patients experience throat irritation. Take sips of water to help reduce irritation. Do not use throat lozenges, as they may affect the results of the test.
Some patients report more difficulty sleeping than usual because they are aware of the probe. Although the probe does not prevent eating or drinking, some patients find these activities somewhat uncomfortable. This discomfort typically lessens as you adjust to the probe being in place.
I am looking for advanced care or a second opinion?
We understand the concerns that come with acid reflux, GERD and heartburn. Whether you are looking for a diagnosis or a second opinion, we’re here to discover the cause of acid-related symptoms you may be experiencing.
The center’s compassionate team of gastroenterologists will test your symptoms and design a personalized treatment plan that works for you and your family.
Bravo Capsule pH Test
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.
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.
Before, During & After the Bravo pH 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:
- We attach a gel cap-sized device — the Bravo capsule — into the inner layer of the esophagus via a delivery system.
- 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.
- 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.
Choose a Doctor at One of Our Locations
Gastroesophageal Reflux Disease (GERD)
Foregut Diseases Program
GI specialists at the Underwood Center provide compassionate care and treatments for patients with GI pain or inflammation.
A program for diseases of the esophagus, stomach and duodenum with challenging causes that require customized treatments.