Lactose breath test for children

In case of complaints of abdominal pain, nausea, bloating, flatulence, burping and/or diarrhoea, as well as indications that these symptoms occur after consuming milk products, a lactose breath test is taken.

If lactose is not absorbed, but remains present in the gut, the lactose will be used as food for bacteria present in the gut. When lactose is broken down by bacteria, a gas is formed: hydrogen. The body removes this hydrogen gas through the exhaled air.

In the lactose breath test, we are going to measure the amount of hydrogen gas in the exhaled air. In a positive test, the amount of this gas increases after ingestion of lactose. In some people (a small group), too few hydrogen-producing bacteria are present and so the test can be (false) negative.

You first register at reception for a lactose breath test. You will receive labels to deliver to the nurse at the outpatients clinic secretariat.

You may report to the secretariat of the paediatrics outpatients clinic at 9am. If you like, may you go to the children's section earlier and see if there are any fun board games or other toys to play with during the test.

It is important that you haven't eaten anything yet. However, drinking water is allowed before the test.

The nurse will ask you to rinse your mouth with an antiseptic solution: Corsodyl.

Through a mouthpiece, you will have to blow into a bag at regular intervals. A syringe is placed on this pouch through which the expelled air is collected. These syringes are numbered from 0 to 18, starting with 0.

You blow the first time before drinking. Then you may drink the lactose drink (sweet).

The nurse sets an alarm clock or uses the timer on the parents' smartphone so you know exactly when to blow into the next bag. The syringes are numbered.

The test takes about three hours. So bring something to play or read.

Before the test

• The day before, eat white bread, no raw vegetables and no more than one piece of fruit (low-fibre diet).
• If you take medication, discuss with the physician whether you can continue taking it.
• Do not take Motilium or laxative medication shortly before the test.
• After taking antibiotics, you should wait four weeks before testing.
• The morning of the test, you should brush your teeth really well.

During the test

• You must not be sick, have a fever, cough heavily or be short of breath when taking the test.
• You should not sleep or chew gum during the test.

You may contact the physician after one to two weeks after the test through the paediatrics secretariat.

Additional info: measurements of the exhaled air are carried out at Ghent University Hospital. You will also receive an invoice from Ghent University Hospital.

Do you have any questions after reading this information? You can always contact your attending physician through the secretariat or a ward nurse: +32 (0)9 387 72 40.

Download the leaflet on lactose breath test for children here.