Urea breath test

Clinical significance
Helicobacter pylori is a spiral-shaped Gram-negative bacterium that colonises the lining of the stomach and can cause chronic gastritis and gastroduodenal ulcers. It is also considered a risk factor for the development of stomach cancer and gastric lymphoma. Transmission of
Helicobacter is faecal-oral, including through food or water, or oral-oral. Factors that help the bacterium settle in the stomach lining include urease activity, motility and the production of factors that change stomach secretion (increased stomach acid). Other conditions possibly associated with Helicobacter infection have been suggested: coronary heart disease, urticaria and pernicious anaemia. The factors toxic to the stomach lining can be divided into direct-acting (cytotoxic) factors encoded by the vacA gene and indirect factors encoded by the cagA gene. cagA-positive strains are those most associated with the risk of developing gastroduodenal ulcers, chronic gastritis and stomach cancer.
The urea breath test uses the bacterium’s ability to break down urea. A solution containing urea labelled with a carbon isotope (C13) is given; it is broken down by urease in the stomach, producing labelled CO2, which is found in the exhaled breath after half an hour.