Hydrogen breath test
The hydrogen breath test is generally used to diagnose lactose or fructose intolerance, bacterial overgrowth of the small bowel or sorbitol malabsorption (an intolerance to the sweetener sorbitol). Typical symptoms include diarrhea, bloating and abdominal pain. The test is performed after a period of fasting and involves the patient ingesting a specific amount of the test substance (such as lactose, fructose, glucose or sorbitol) dissolved in water or unsweetened peppermint tea. The patient is then asked to breathe into a testing device prior to ingestion of the liquid and at regular intervals up to 2 hours afterwards. An increased level of H2 in the exhaled breath may indicate abnormal function. Another important aspect of testing is to record any symptoms that arise during testing. Test results can be interpreted immediately upon completion of testing.