Urea breath test. A urea breath test checks to see if you have H. pylori bacteria in your stomach. This test can show if you have an H. pylori infection. It can also be used to see if treatment has worked to get rid of H. pylori. Stool antigen test. A stool antigen test checks to see if substances that trigger the immune system to fight an H. pylori infection (H. pyloriantigens) are present in your feces (stool).