A simple, painless way to diagnose fructose intolerance is to perform a so-called H2, or hydrogen breath test. In this test, fructose that is not digested or absorbed in the small intestine is fermented in the large intestine into acids and gases (such as hydrogen) when exposed to fructose - and the higher hydrogen levels can be detected in the exhaled air.
Presentation of the test
In the H2 breath test, the patient's mouth and throat are first rinsed with an antibacterial agent. The patient then ingests a glass of fructose-containing test fluid. Afterwards, every 20 minutes, the patient breathes into the test device, which tests the amount of hydrogen absorbed - fructose intolerance is associated with high hydrogen levels. Of course, we also record if typical symptoms of fructose intolerance appear. The total time of the test is 180 minutes, most of which is waiting time - so it's a good idea to bring a good book!
What to know about the test
The test should not be performed in case of fever or viral illness. For younger children, the strictness of the diet is set by the doctor. Please adhere strictly to the following instructions, otherwise the test may give a false abnormal result!
Do not take before the test:
Antibiotics, probiotics within one month
Within one week, antacids and digestive medications
Within two days
Diet from the morning of the day before the test:
do not eat: fruit, vegetables, pulses, puffy foods, stews, or foods in which vegetables have been cooked
do not eat: dairy products and milk, lactose-containing foods, pastries with milk, chocolate, oil seeds, foods with significant amounts of fat and oil
no carbonated drinks, fruit juice, alcohol (no smoking)
What you can eat and drink:
cooked, natural fried or steamed: potatoes, rice, ham, poultry, fish, eggs, pasta
lactose-free cold cuts and sausages, lactose-free margarine
white flour buns, rolls, bread (without seeds)
non-carbonated mineral water
Do not eat anything after 7 p.m. and do not drink anything after 9 p.m. until the test!
Brush your teeth thoroughly the evening before the test.
The test is done on an empty stomach and takes 3 hours. On the morning of the test and again immediately before the test, it is recommended to brush your teeth thoroughly WITHOUT BRUSHING (brushing water must not be swallowed).
Do not take your child's morning medication, toothpaste, mouthwash, lipstick, gum or candy before the test.
Settlement also to a health fund account
The fee for the examination can of course also be charged to your health insurance account - our colleagues will be happy to provide you with more details. Visit
Find a list of health insurance providers affiliated with Endomedix here.
For more details, please call us on +36 1 413 2500 or
contact us online.
Related examinations
The hydrogen absorption test is not only suitable for detecting fructose intolerance. A
H2 breath test - lactose using lactose sensitivity, while the
H2 breath test - lactulose to detect contaminated small bowel syndrome.
