Hydrogen breath test

This test measures the amount of hydrogen in the breath and helps diagnose several digestive problems, including carbohydrate intolerance, bacterial overgrowth of the small intestine and rapid transit of food through the small intestine. Normally, digestive enzymes in the stomach and upper small intestine digest carbohydrates in the food we eat. Bacteria in the lower small intestine digest the rest of the carbohydrates and produce hydrogen gas in the process. If carbohydrates are largely undigested by the time they reach the small intestine, bacteria will complete the digestive process; however, hydrogen gas being produced will cause cramps and bloating. This can happen if the carbohydrates are not digested properly, if food moves through the digestive system quickly or if there are large numbers of bacteria present. The amount of hydrogen in the breath is greater than usual when bacteria in the intestines digest carbohydrates instead of digestion being done by the normal digestive enzymes.

For this test, your child will fast overnight and then blow into a balloon periodically. Your child will be given samples of a carbohydrate (such as lactose or sorbitol) to drink. The amount of hydrogen produced in your child’s breath will be measured at the start of the test, and at intervals after he or she consumes the carbohydrates.

Related conditions:

• Lactose intolerance
• Malabsorption
• Helicobacter pylori
• Peptic ulcers

Related services:

• Lactose intolerance
• Malabsorption