An H. pylori test is a medical test that is used to detect the presence of Helicobacter pylori (H. pylori) bacteria in the stomach. H. pylori is a type of bacteria that can cause stomach ulcers and gastritis. There are several different types of H. pylori tests, including: Stool antigen test: This test looks for antigens to H. pylori in the stool. Urea breath test: This test measures the amount of carbon dioxide in the breath after the patient drinks a liquid containing urea. If H. pylori is present in the stomach, it will break down the urea and produce carbon dioxide. Serology test: This test measures the antibodies to H. pylori in the blood. Endoscopy: This test involves inserting a thin, flexible tube with a camera into the stomach to look for signs of H. pylori infection. The type of H. pylori test that is used will depend on the patient's symptoms and the doctor's suspicion of infection. The H. pylori test is a simple and painless procedure. However, there are some risks associated with any medical test, including: Bleeding at the needle site. Infection. Allergic reaction to the needle or the test solution. It is important to talk to your doctor about the risks and benefits of the H. pylori test before having the test. Here are some of the reasons why your doctor might order an H. pylori test: You have symptoms of stomach ulcers, such as pain in your upper abdomen, nausea, and vomiting. You have a family history of stomach ulcers. You have been exposed to H. pylori, such as through contact with someone who has the infection. You are taking medications that can increase your risk of H. pylori infection, such as nonsteroidal anti-inflammatory drugs (NSAIDs). If you have an H. pylori test, it is important to follow your doctor's instructions. This may include taking antibiotics to treat the infection.