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Lahey Health is now part of Beth Israel Lahey Health

by EBSCO Medical Review Board


Esophageal pH monitoring measures how much acid is in the tube that joins the mouth to the stomach. A small pod is placed in the tube. It will send data to a receiver device worn on the waist.

Reasons for Procedure

pH is monitored to test how much acid is moving up from the stomach. It can also show how long the acid stays there. This will help to plan or track treatment for gastroesophageal reflux disease (GERD).

Possible Complications

Problems are rare, but all procedures have some risk. Your doctor will go over some problems that may happen, such as:

  • The capsule becomes loose
  • Sore throat
  • Anesthesia problems
  • Infection
  • Bleeding
  • Chest pain
  • Problems swallowing when food passes by the capsule
  • Harm to the esophagus

Before your procedure, talk to your doctor about ways to handle things that may raise your risk of problems, such as:

  • Long-term diseases like diabetes
  • Bleeding problems
  • The use of certain medicines

What to Expect

Prior to Procedure

Leading up to your procedure:

  • Arrange for a ride to and from the care center. Also, arrange for someone to help you at home.
  • Talk to your doctor about your medicines. You may be asked to stop taking some up to 1 week before surgery.
  • Tell your doctor about any allergies you may have.
  • Do not eat or drink after midnight the night before surgery.


You may have:

  • Moderate sedation—you will be sleepy and may not feel pain
  • Local anesthesia—your throat will be numbed

Description of the Procedure

A long tube with a light and camera will be put in your mouth. You will be asked to try to swallow it. The camera will show where the tube is. Once it is in the right place, the pod will be connected to tissue. The tube will be removed.

The capsule will fall off in about a week. It will pass through the body in stool.

How Long Will It Take?

30 minutes

Will It Hurt?

You will have some discomfort during the test. Your throat will be sore for 1 to 2 days after the procedure. Over-the-counter pain medicine can help if needed.

Post-procedure Care

At the Care Center

The staff will check on your progress until the anesthesia wears off.

You will be given the receiver that collects the data. Your care team will tell you how to wear it and for how long.

At Home

The monitor will need to be worn for about 48 hours.

Call Your Doctor

Call your doctor if you have:

  • Signs of infection, such as fever and chills
  • Problems swallowing or breathing
  • Nausea and vomiting
  • Cough
  • Chest pain
  • Bleeding
  • Problems using the receiver

If you think you have an emergency, call for emergency medical services right away.


American Gastroenterological Association 

American Society for Gastrointestinal Endoscopy 


Canadian Digestive Health Foundation 

Health Canada 


Ambulatory pH monitoring. Merck Manual Professional Version website. Available at: Accessed June 28, 2020.

Esophagus: 48-hour Bravo esophageal pH test: Test details. Cleveland Clinic website. Available at: Accessed June 28, 2020.

National Institute for Health and Clinical Excellence (NICE). Dyspepsia and gastro-esophageal reflux disease: Investigation and management of dyspepsia, symptoms suggestive of gastro-esophageal reflux disease, or both. NICE 2014 Sep:CG184.

Preparing for reflux testing. Medtronic website. Available at: Accessed June 28, 2020.

Revision Information