Helicobacter pylori (H. pylori) is a small, spiral-shaped bacterium that is found on the surface of the stomach (epithelial lining) and duodenum (mucous layer). H. pylori causes duodenal ulcers and gastric ulcers. 

The importance of Helicobacter pylori testing has increased greatly since the strong correlation between the presence of bacteria and confirmed gastrointestinal diseases (stomach and duodenum) like gastritis, peptic ulcer disease and gastric carcinoma. Invasive and non-invasive methods are used to diagnosis H. pylori infection in patients with symptoms of gastrointestinal disease.