Principle and Clinical Application of the Hydrogen Breath Test

Abstract

Small intestinal bacterial overgrowth (SIBO) is associated with a variety of gastrointestinal and hepatobilliary diseases. The hydrogen breath test can be used to diagnose malabsorption or intolerance of lactose or fructose, as well as to confirm SIBO. The hydrogen breath test used as a diagnostic tool for SIBO is simple and easy to perform. However, its sensitivity and specificity vary according to the materials used and the method of analysis. In the lactulose breath test, the diagnostic criterion using the early increase in the hydrogen concentration in the exhaled air may produce false positive results when the orocecal transit time is short. The other diagnostic criterion involving the assessment of the two peaks of hydrogen level has the disadvantage of low sensitivity and is not recommended. In the glucose breath test, a false negative result can be a problem when SIBO is present only in the distal small intestine. The choice of methodology may be affected by the suspected location of SIBO and intestinal transit time. Methane gas measurement is important, particularly in patients with constipation. The diagnostic criteria and test methodology to increase sensitivity, indications for use, and relationship of SIBO with patient’s symptoms need to be established.