Breath testing measures the hydrogen and methane gases produced by bacteria in the small intestine that has diffused into the blood, then lungs, for expiration. These gases are produced by bacteria, yeast or archaea, not by humans, and are tracked on a graph over the small intestine transit time of 2-3 hours. A sugar solution of glucose or lactulose is taken after a 1 or 2 day preparatory diet, which removes much of the food that would feed the bacteria, allowing for a clear reaction to the sugar drink. There are two types of breath test: lactulose and glucose. Please ensure you choose the correct challenge agent when ordering:
Glucose Breath Test
Both humans and bacteria absorb glucose, and this should occur within the first three feet of the SI, therefore if the bacterial gases of H and/or M are produced during this test, it reflects an overgrowth in the proximal/upper end of the SI (within the first two feet). This test successfully assesses proximal SI overgrowth, but can not assess distal overgrowth which is thought to be more common.
The test is performed at home. There should be a 24-48 hour preparation diet prior to starting the test, which should be started after an overnight fast (12 hours), and will take 3 hours to collect the samples at timed intervals.
A sample report can be viewed here.