Tests and procedures used to determine whether you have an H. pylori infection include:
- Blood test. Analysis of a blood sample may reveal evidence of an active or previous H. pylori infection in your body. However, breath and stool tests are better at detecting active H. pylori infections than is a blood test.
Breath test. During a breath test, you swallow a pill, liquid or pudding that contains tagged carbon molecules. If you have an H. pylori infection, carbon is released when the solution is broken down in your stomach.
Your body absorbs the carbon and expels it when you exhale. You exhale into a bag, and your doctor uses a special device to detect the carbon molecules.
Acid-suppressing drugs known as proton pump inhibitors (PPIs), bismuth subsalicylate (Pepto-Bismol) and antibiotics can interfere with the accuracy of this test. Your doctor will ask you to stop taking those medications for a week or two weeks before you have the test. This test is available for adults and children.
- Stool test. A laboratory test called a stool antigen test looks for foreign proteins (antigens) associated with H. pylori infection in your stool. As with the breath test, PPIs and bismuth subsalicylate can affect the results of this test, so your doctor will ask you to stop taking them for two weeks before the test.
Scope test. You'll be sedated for this test, known as an upper endoscopy exam. During the exam, your doctor threads a long flexible tube equipped with a tiny camera (endoscope) down your throat and esophagus and into your stomach and duodenum. This instrument allows your doctor to view any irregularities in your upper digestive tract and remove tissue samples (biopsy).
These samples are analyzed for H. pylori infection. This test isn't generally recommended solely to diagnose an H. pylori infection because it's more invasive than a breath or stool test, but it may be used to diagnose H. pylori ulcers or if it's needed to rule out other digestive conditions.