Health Encyclopedia

Esophageal pH monitoring

Definition

Esophageal pH monitoring is a test that measures how often and for how long stomach acid enters the tube that leads from the mouth to the stomach (esophagus).

Alternative Names

pH monitoring - esophageal; Esophageal acidity test

How the test is performed

A thin tube is passed through your nose or mouth to your stomach. Then it is pulled back into your esophagus. The tube is attached to a monitor that measures the level of acidity in your esophagus.

You will wear this monitor on a strap and will be asked to keep a diary of your symptoms and activity over the next 24 hours. The next day you will return and the tube will be removed. The information from the monitor will be compared with the diary notes you provide.

Infants and children will most likely remain in the hospital for the esophageal pH monitoring.

How to prepare for the test

Your health care provider will ask you to not eat or drink (fast) and avoid smoking after midnight before the test.

Some drugs may change the test results. Your health care provider may ask you to not take those drugs for 24 hours to 2 weeks (or more) before the test, depending on the medication. These substances may include:

Adrenergic blockers
Alcohol
Antacids
Anticholinergics
Cholinergics
Corticosteroids
H2 blockers
Proton pump inhibitors

Do not stop taking any medication unless told to do so by your health care provider.

How the test will feel

You may experience a brief gagging sensation as the tube is passed through your throat.

Why the test is performed

Esophageal pH monitoring is used to check how much stomach acid is entering the esophagus, and how well it is cleared downward into the stomach. It is a test for gastroesophageal reflux disease (GERD).

This test can also be performed during upper GI endoscopy by clipping a pH monitoring device to the lining of the esophagus. In infants, this test is also used to check for GERD and related excessive crying or other problems.

Normal Values

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

Increased acid in the esophagus may be a sign of:

Barrett's esophagus
Difficulty swallowing (dysphagia)
Esophageal scarring
Gastroesophageal reflux disease (GERD)
Heartburn
Reflux esophagitis

If you have esophagitis, you may need these additional tests:

Barium swallow
Esophagogastroduodenoscopy (also called upper GI endoscopy)

What the risks are

No significant risks have been reported with this test, but the following may occur rarely:

Arrhythmias during insertion of the tube
Breathing in of vomit if the catheter causes vomiting (see aspiration of vomitus)

References

Orlando RC. Diseases of the esophagus. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 140.

Review Date:11/2/2008
Reviewed By:David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.