Testing gastro­intestinal function

In some gastroenterology patients it is necessary to go beyond the types of screening tests outlined above, and to assess the function of specific organs or organ systems or other apparent functional disorders. Some of these types of investigations make use of certain substances that have to be ingested by the patient and are then metabolized by the body, allowing the physician to measure the metabolites once they leave the body. Some of these substances may be metabolized by the body to produce CO2 or H2, both of which can be measured in the patient’s exhaled breath.

(C13) urea breath test

Hydrogen breath test