Breath tests in gastroenterological functional diagnostics. Basics and clinical applications

A number of gastrointestinal functional tests contain invasive test procedures or the use of ionizing radiation and breath tests provide patient-friendly and cost-effective alternatives. With the hydrogen breath test carbohydrate malabsorption and bacterial over-growth can be detected. (CO2)-C-13 breath tests with stable C-13-isotopes can be used to investigate a variety of gastrointestinal organ functions. Numerous C-13-marker substances and test procedures are available for the diagnosis of motility disorders of the stomach and the small intestine. Gastric emptying measurements of liquid or solid meals are well established in clinical practice for the diagnosis of gastroparesis. However, the derivation of typical physiological parameters of gastric emptying and intestinal transit may cause difficulties. In this article the basic mode of function, common test meals, the practical standardized execution and interpretation of breath tests in gastrointestinal functional testing are described.