What Happens During the Hydrogen Breath Test?
During the hydrogen breath test, which at the Cleveland Clinic lasts about 2 hours, you will be asked to drink a lactose-containing beverage. The beverage may cause cramping, bloating, gas, or diarrhea. Fifteen minutes after drinking the beverage, you will be instructed to blow up balloon-like bags every 15 minutes for two hours. The air you breathe into these bags is tested frequently for the presence of hydrogen. Normally, very little is detected in breath. However, hydrogen and other gases are produced when undigested lactose in the colon is fermented by bacteria. Raised hydrogen breath levels indicate the improper digestion of lactose, which could lead to a diagnosis of lactose intolerance or the presence of abnormal bacteria in the colon.
