D -xylose breath test

D-xylose breath test,

a breath test for bacterial overgrowth in the intestine in which the fasting patient is administered a dose of D-xylose labeled with carbon 14 and the amount of radiolabeled carbon dioxide in the breath is measured at regular time intervals. Excessive levels of carbon dioxide mean that there are high levels of anaerobic bacteria in the intestines breaking down the xylose.