[Possibilities for use and limits of the H2 breath test in gastroenterologic diagnosis].

The H2 breath test is a non-invasive, safe, and - using modern analytical equipment - simple and non-expensive investigation, which reflects gastrointestinal bacterial fermentation of carbohydrate. It is widely used to study sugar malabsorption, and, with mainly scientific intent, also that of complex carbohydrates. The test plays an important role in the investigation of upper intestinal motility disturbances as it is suitable to monitor the orocaecal transit time. Furthermore, the test seems to offer valuable information for the study of upper intestinal bacterial overgrowth. However, a standardized test design for the latter purpose is lacking so far. The H2 breath test is an indirect investigation method and therefore requires careful consideration of multiple potentially interfering factors.