Breath hydrogen and methane tests are used to determine intolerances to both lactose (the sugar found in milk) and/or fructose (the sugar found in honey and many fruits). In order to maximise the accuracy and information obtained from a breath test, the first breath test is a control test, using lactose (a mild laxative), which everyone will have a reaction to. The control test is done to determine whether you are a hydrogen producer or a methane producer to insure that the subsequent breath tests will be measuring the most appropriate gas for you.
Normally the sugars that we ingest every day are absorbed within the small bowel, but a large proportion of people absorb these sugars poorly, allowing the sugars to pass into the large bowel. When these improperly absorbed sugars react with the bacteria in the large bowel, a gas is produced, either hydrogen or methane, and in turn this is absorbed into the blood stream and travels to the lungs where it is breathed out, and can be detected through these breath tests . If someone is producing high levels of hydrogen or methane gas (causing a reaction), once the lactose or fructose sugar has been ingested, this suggests it is not being absorbed properly in the small bowel and indicates an intolerance to that particular sugar.
The breathalyser used at the MacMurray Centre only detects hydrogen gas when it is breathed out from the lungs.