What to expect from an H. pylori breath test for gastritis

The test looks for carbon dioxide produced when H. pylori breaks down the test substance. A positive result supports current H. pylori infection, which can irritate the stomach lining and contribute to gastritis. A negative result makes active infection less likely, although preparation and recent medicines can affect accuracy. The test does not show every cause of gastritis or measure how irritated the stomach lining is.

Follow the testing centre's fasting instructions and tell the clinician about antibiotics, acid-suppressing medicines, bismuth products, and other treatments. Some of these may need to be stopped for a clinician-specified interval, so do not change prescribed treatment without advice. Avoid smoking during the preparation period if instructed. The appointment is usually simple and does not involve needles or an instrument passing into the stomach.

Contact a clinician promptly for vomiting blood, black or tarry stools, severe or worsening upper-abdominal pain, fainting, or trouble swallowing. These symptoms need assessment rather than waiting for a breath-test result. Arrange follow-up if symptoms continue after a negative test, because gastritis can have causes other than H. pylori.

Ask whether you need to fast, which medicines to pause, when a result will be available, and whether a positive result would change your treatment. If treatment is given, ask how its success will be checked and when a repeat test would be appropriate.