The 13C or 14C-urea breath test and the rapid urease test can be used to know definitively if you are infected with H. pylori. 1. 13C or 14C-urea breath test. H. pylori can produce highly active urease, which can break down the 13C or 14C-labeled urea taken by the patient into ammonia and labeled CO2, thus clarifying the presence of H. pylori. 2. Rapid urease test. Take a piece of gastric mucosa tissue during gastroscopy, put it into the test reagent, if the actual color changes from yellow to red, it means there is H. pylori infection. If you suspect that you are infected with H. pylori, you should go to the hospital in time for relevant examinations and treatment under the guidance of your doctor to avoid delaying your condition.