Helicobacter pylori tests are used to detect a Helicobacter pylori (H. pylori) infection in the stomach and upper part of the small intestine (duodenum). H. pylori can cause peptic ulcers; however, most people with H. pylori in their digestive systems do not develop ulcers.

Four tests are used to detect H. pylori:

• Blood antibody test. A blood test checks to see whether your body has made antibodies to H. pylori bacteria. If you have antibodies to H. pylori in your blood, it means you either are currently infected or have been infected in the past.
• Urea breath test. A urea breath test checks to see if you have H. pylori bacteria in your stomach. The breath test is not always available.
• Stool antigen test. A stool antigen test checks to see if substances that trigger the immune system to fight an H. pylori infection (H. pylori antigens) are present in your feces (stool). Stool antigen testing may be done to help support a diagnosis of H. pylori infection or to determine whether treatment for an H. pylori infection has been successful.
• Stomach biopsy. A small sample (biopsy) is taken from the lining of your stomach and small intestine during an endoscopy. Several different tests may be done on the biopsy sample. For more information, see the medical test Upper Gastrointestinal Endoscopy.

Why It Is Done

A Helicobacter pylori (H. pylori) test is done to:

• Determine whether an infection with H. pylori bacteria may be causing an ulcer or irritation of the stomach lining (gastritis).
• Determine whether treatment for an H. pylori infection has been successful.

How To Prepare

Blood antibody test or stool antigen test

You do not need to do anything before you have a blood antibody test or stool antigen test.

Stomach biopsy or urea breath test

Do not eat or drink for at least 6 hours before a breath test or a stomach biopsy.

Many medicines may change the results of this test. Be sure to tell your doctor about all the prescription and nonprescription medicines you take. Your doctor may recommend that you stop taking some of your medicines for up to 1 week before having this test.

• Do not take antibiotics, proton pump inhibitors (such as Prilosec or Nexium), or medicines containing bismuth (such as Pepto-Bismol) for 1 to 2 weeks before the test.
• Do not take H2 blockers, such as Pepcid AC, Zantac, Axid, or Tagamet, for 24 hours before the test.

Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).