At a Glance
Why Get Tested?
To diagnose an infection with Helicobacter pylori
When to Get Tested?
If you have gastrointestinal pain or symptoms of an ulcer
A stool sample, blood sample from a vein, tissue biopsy of the stomach lining, or a breath test
Test Preparation Needed?
None for the blood test; there are instructions for the breath test.
The Test Sample
What is being tested?
These tests are looking for evidence of an infection by a bacterium, known as Helicobacter pylori. This bacterium is now known to be a major cause of peptic ulcer disease. H. pylori is also associated with the development of gastric cancer.
How is the sample collected for testing?
What is collected depends on the test your doctor requests. It may be as simple as submitting a stool (faecal) sample to look for the H. pylori antigen or a blood sample from your vein to detect an antibody to the bacteria.
A more invasive test will require a procedure called an endoscopy, which means putting a tube down the throat into the stomach to take a small piece of tissue (a biopsy) from the stomach lining. A biopsy can be used to detect other reasons for stomach pain, as well as be tested in the laboratory for H. pylori. H. pylori produces urease, a special enzyme that allows it to survive in the acidic environment of the stomach.
The laboratory can detect the presence of this bacterium by looking for this enzyme in the tissue sample. The tissue may also be examined under a microscope by a pathologist, who will look for these bacteria or any other signs of disease that may explain your symptoms.
Sometimes a breath test can be used instead of a biopsy. You will be asked to drink a special liquid containing a harmless radioactive material. If H. pylori is present in your GI tract, the material will be broken down into radio-labeled carbon dioxide gas. By testing the expelled air collected from your breath sample, the laboratory can determine if this organism is in your body.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.