In Helicobacter pylori infection which is the most common cause of gastritis, a non-invasive test such as the urea breath test is used to determine the presence of H. pylori in the stomach.

• Urea breath test identifies active H. pylori infection.^[1][2]
• Procedure:

• The urea labeled with either the nonradioactive isotope ¹³C or the radioactive isotope ¹⁴C is ingested.
• The H. pylori urease converts labeled urea to CO₂, which can be quantitated in expired breath.

• ¹³C labeled urea is preferred in children and pregnant females.
• The urea breath test has 95% sensitivity and specificity.^[3]
• This test is an accurate means of post-treatment testing.^[4][5]
• As this test mainly depends on urease activity of H. pylori, the sensitivity of the test is decreased by medications such as bismuth containing products, PPIs, and antibiotics as they reduce organism density or urease activity. It is recommended to withhold PPIs for 7-14 days prior to the test, and bismuth and antibiotics are withheld for at least 28 days.^[6][7][8]
• Antacids do not affect the efficacy of the test.^[9]

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