Hydrogen breath test
WHAT IS THE PURPOSE OF THIS DOCUMENT RELATING TO HYDROGEN BREATH TESTING?
We want to provide you with information, before the procedure, about the examination you will undergo and the related risks. The information is intended to alleviate any justifiable concerns and misapprehensions you may have.
WHAT IS A HYDROGEN BREATH TEST?
The hydrogen breath test is used to detect carbohydrate malabsorption, i.e. to identify excessive production of intestinal gases or intestinal bacterial overgrowth.
- Lactose: to identify milk sugar malabsorption, which is also called lactose malabsorption
- Fructose: to identify malabsorption of fructose, the main sugar present in fruit
- Lactulose: to identify bacterial overgrowth in diabetic patients
- Glucose: to identify intestinal bacterial overgrowth. Because of the osmotic effect of the sugar in question and the fermentation it undergoes in the intestinal lumen among tested patients, the consumption of this sugar causes a malabsorption syndrome that translates into various disorders, such as bloating, flatulence, stomach pain, or watery diarrhea. The sugar that reaches the colon causes the formation of hydrogen (H2) by the intestinal flora: molecular hydrogen passes through the intestinal wall and can be measured in the air you exhale. This is why an increased concentration of hydrogen in exhaled air (more than 20 ppm) can be used to detect the disease.
HOW DO I PREPARE FOR THE TEST?
- 15 days before the test: do not take any antibiotics.
- For two days before the test, you are asked to refrain from eating legumes (cereal, lentils, beans, bean sprouts, green peas, chickpeas) or any other foodstuff that causes flatulence. If possible, refrain from eating sugar (in its natural form), dairy products, or fruit, as this could affect the accuracy of the test.
- The evening before the test: eat a light meal at 8pm at the latest. Do not eat beans, peas, root crops (carrot, beetroot, kohlrabi, horseradish, etc.), lentils, fruit, berries, honey, pasta, bread, chewing-gum, or dairy products (including milk, yoghurt, packet soups or sauces, cream, ice-cream. Butter and hard cheeses are allowed). The ideal meal consists of rice with white meat and without sauce or fruit. Do not drink alcohol or beer.
- Starting at 10pm, do not ingest anything except for flat water up to two hours before the test.
- On the morning of the examination, take your usual medication with a glass of flat water (non-fizzy) and follow strict fasting rules (i.e. no breakfast). It is important to refrain from brushing your teeth or wearing perfume. You must also refrain from smoking as this will affect the results of exhaled air measurements. If you are diabetic, make sure not to take insulin on the morning of the examination, as per fasting rules. Take your blood glucose measuring device for the examination so you can check your levels as necessary.
HOW IS THE TEST CONDUCTED?
- As you arrive, you will be asked to blow into a nozzle connected to an analysing device to measure the quantity of hydrogen you exhale. You will then be asked to swallow tested sugar in water at room temperature (maximum 1 g/kg of body weight). Then, for two to four hours, you will be asked to blow into the nozzle every 30 minutes to measure the hydrogen you exhale after having absorbed the tested sugar. Any symptom you display will be recorded. An H2 increase of more than 20 ppm from the initial measurement and symptoms such as bloating, stomach cramps, and diarrhea are indicative of intolerance to the type of sugar in question. For the duration of the test, you will not be allowed to eat or smoke. You will, however, be allowed to drink flat water after two hours.
- Bring reading material or something to occupy yourself (WiFi is available).
- You will remain in the medical unit for three to five hours.
WHAT ARE THE RISKS OF THIS TEST?
The digestive symptoms you might feel (bloating, stomach cramps, diarrhea) are precisely the ones the test is intended to investigate. In rare cases, faintness has been reported with no severe consequences.
WHAT QUESTIONS SHOULD YOU ASK ?
You should ask your doctor any question you deem relevant before the test. We are happy to answer any question you may have at 02/614.37.10.
