The hydrogen breath test is based on measuring the concentration of hydrogen (H₂) in the exhaled air.

Hydrogen is produced in the large intestine by the bacterial breakdown of various sugars. In some sugar intolerances, there are too few enzymes to break down the sugars, so the sugars enter the colon, where bacterial decomposition occurs and hydrogen is produced as a metabolic product. The hydrogen is absorbed by the blood, exhaled through the lungs and can thus be measured in the exhaled air.

In practice, tests are offered to exclude an intolerance to lactose and fructose. In addition, a test with glucose can also be routinely performed to diagnose bacterial malabsorption.

Preparation for the H2 breath test

You should not have taken any antibiotics or had a colonoscopy up to 4 weeks before the test.

The day before the test, you should not eat any dairy products or sweet foods. You should not eat any food from 8pm the evening before, drinking water is allowed. On the morning of the examination, please remain sober.

The test begins with the determination of the zero value, i.e. the hydrogen then present in the exhaled air. Then a sugar solution is drunk (depending on the test: lactose, fructose, glucose or other sugars). Depending on the test substance, a measurement is taken every 15 minutes over a period of 120 minutes. In the case of abnormal values, longer if necessary.

In case of intolerance, a defined and clear increase of hydrogen in the exhaled air is measured. We will then discuss the results with you.