Hydrogen breath test after glucose load

Glucose loaded hydrogen breath test

Hydrogen breath test (HBT) allows to determine the concentration of hydrogen in exhaled air, following the administration of glucose to the patient. Hydrogen is produced through fermentation by bacteria present in the large and small intestines. In the course of certain diseases, some of the carbohydrates ingested with food are not digested and undergo fermentation. The hydrogen breath test (HBT) is mainly performed as part of the diagnosis of small intestinal bacterial overgrowth (SIBO).

The test involves measuring hydrogen levels in the breath the patient exhales before consuming a certain amount of sugar and then after drinking sugar dissolved in water at set intervals.

The test is performed in adults and in children aged 10 years and older.

The test is not recommended if less than 4 weeks have passed since the patient stopped taking antibiotics. Relative contraindications include the following:

• taking probiotics up to 4 weeks before the test;
• radiography and colonoscopy in 4 weeks before the test;
• ileostomy.

To reduce the risk of false results, 1–2 days before the test:

• eat low-fibre foods;
• limit your consumption of lactose (products such as lactose-free milk, cheese and vegetable drinks are allowed);
• limit your consumption of fruit (less than 1 handful every 3 hours);
• do not eat products that cause bloating (e.g. dry pulses);
• do not drink alcohol.

How to prepare for the test?

The day before the test, avoid taking vitamins, minerals, laxatives or stool thickening products (unless they are necessary).

Do not eat anything 8–12 hours before the test. You can drink still water (unsweetened and unflavoured), but you should not drink large amounts of water in the morning on the day of the test.

On the day of the test, do not do physical activity, do not smoke, do not chew gum, do not use strong perfumes or aftershaves and do not put on lipstick.

In the morning on the day of the test, if possible, avoid taking medicines (unless it is contraindicated for medical reasons).

Before the test, brush your teeth thoroughly and rinse your mouth (do not use mouthwashes or oral rinses). Do not use denture adhesives.

As the test takes some time, you may want to take a newspaper or book to read.

In order to undergo the test, please make sure to obtain a referral from a doctor