Urea Breath Test (UBT) Procedure

  • Medical Author:
    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What is the urea breath test?

The urea breath test (UBT) is a test for diagnosing the presence of a bacterium, Helicobacter pylori (H. pylori) infection in the stomach. H. pylori causes inflammation, ulcers, and atrophy of the stomach. The test also may be used to demonstrate that H. pylori has been eliminated by treatment with antibiotics.

What is the preparation for the urea breath test? How is it performed?

You're doctor or other healthcare professional will proide you with unstructions to prepare for the urea breath test.

During the test you will swallow a capsule containing urea, which is made from an isotope of carbon. (Isotopes of carbon occur in minuscule amounts in nature, and can be measured with special testing machines.) If H. pylori is present in the stomach, the urea is broken up and turned into carbon dioxide. The carbon dioxide is absorbed across the lining of the stomach and into the blood. It then travels in the blood to the lungs where it is excreted in the breath. Samples of exhaled breath are collected, and the isotopic carbon in the exhaled carbon dioxide is measured.

How does the urea breath test diagnose H. pylori infection?

The urea breath test is based on the ability of H. pylori to break down urea, a chemical made up of nitrogen and carbon into carbon dioxide. which then is absorbed from the stomach and eliminated in the breath. (Urea normally is produced by the body from excess or "waste" nitrogen-containing chemicals and then eliminated in the urine.)

How are the results of the urea breath test interpreted?

If the urea breath test is positive and the isotope is detected in the breath, it means that H. pylori is present in the stomach. If the isotope is not found in the breath, the test results are negative for the infection.

When the H. pylori is effectively treated (eradicated) by antibiotics, the test changes from positive (isotope present) to negative (isotope absent).

Are there any side effects, risks, or complications of the urea breath test?

There are no side effects, risks, or complications of the urea breath test. You do not need to stop taking medications, including proton pump inhibitors (PPIs), prior to having the procedure performed by a doctor.

Quick GuideDigestive Disorders: Common Misconceptions

Digestive Disorders: Common Misconceptions
Medically Reviewed on 7/16/2018
References
REFERENCES: Crowe, Sheila E., MD, FRCPC, FACP, FACG, AGAF. "Indications and diagnostic tests for Helicobacter pylori infection." UptoDate.com. Updated: June 2018.

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