glucose breath test

Last reviewed 01/2018

The glucose breath test may be used to investigate bacterial overgrowth in the small intestine. After an oral dose of 50 g of glucose in 180 ml of water, end-expiratory breath hydrogen is assessed for 2-3 hours at 15-30 minute intervals. Contamination is indicated by a rise in hydrogen as the glucose enters the small bowel, often to as much as 100 ppm. The test has a sensitivity above 90% with a specificity of about 80%.

Lactulose may be substituted for glucose.