A hydrogen breath test is an easy way of diagnosing lactose or fructose intolerance in adults and children. The test, which aims to establish whether there is lactose or fructose intolerance, is easy to carry out and causes no detriment to the patient. However, he/she must prepare him-/herself thoroughly in the weeks and days before the test.

The principle underlying hydrogen breath tests

The hydrogen breath test is based on a measurement of the hydrogen given off by the bacterial decomposition of sugar in the digestive tract.

Normally, sugars (such as lactose or fructose) are metabolised in the small intestine by certain enzymes. Food intolerances are caused by these enzymes not working properly:

Lactose intolerance: insufficient activity of the enzyme lactase; lactose is therefore not broken down into its constituent parts glucose and galactose in the small intestine

Fructose intolerance /-malabsorption: reduced function of the GLUT5-transporter causes insufficient absorption of fructose from the small intestine

Procedure for a hydrogen breath test

At the start of the test, the base value of the patient’s breath is tested (the patient must be fasting). The patient blows into a small, hand-held device similar to the breathalisers used by police to test for alcohol. The device shows the concentration of hydrogen in the breath.

The patient then drinks a glass of water which has 50g lactose or 25g of fructose dissolved in it, depending on the test being done. The concentration of hydrogen in the breath is measured in intervals of 30 minutes. The results are available after two, but at the latest three hours.

During the test, the doctor also looks for signs of other sugar-related complaints such as bloating, stomach cramps and diarrhoea. However, these frequently only occur later in the afternoon.

Appointments required:
Mo-Fr 7 am – 4 pm
please use E: termin1090@ihrlabor.at
or call T: +43 1 408 31 31

Beginning and duration of test:
Beginning of test: Mo-Fr 7:30 am-8 am
Duration of test: up to 3 hours
Please note the instructions for preparation.

EUR 40 per test
The costs are general reimbursed under private insurance.

Payment options:

  • Cash
  • Debit card
  • Credit card (Visa, Mastercard, V-Pay)

Please note the instructions for preparation. Failure to follow these instructions can result in inaccurate test results.