Lactose intolerance breath test (lactose intolerance hydrogen breath test)
The hydrogen breath test is a simple and safe method used to diagnose lactose malabsorption, or impaired lactose absorption.
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How to prepare
The hydrogen breath test is a simple and safe method used to diagnose lactose malabsorption, or impaired lactose absorption. During the test, the patient drinks a solution containing a specific amount of lactose, and the amount of hydrogen in the breath is measured at set intervals. If lactose is not properly absorbed in the small intestine, it reaches the large intestine, where it is broken down by bacteria, producing hydrogen and other gases. These gases are absorbed into the bloodstream and exhaled, so elevated hydrogen levels in the breath indicate lactose malabsorption and possible lactose intolerance caused by a deficiency of the lactase enzyme. This test usually takes about 2–3 hours.
How should I prepare for the exam?
Four weeks before the test:
- Do not take antibiotics.
Two weeks before the test:
- Do not take probiotics, magnesium, or omeprazole.
- Do not take laxatives, stool softeners, or stool bulking agents. You should also avoid any tests that require bowel preparation, such as a colonoscopy or barium enema.
Two to three days before the test:
- It is recommended to consume only the following foods and beverages: white bread, white rice, white potatoes, baked or grilled chicken or fish, water, and black coffee or tea without flavoring.
- Do not eat or drink anything else—this may lead to inaccurate test results.
- In particular, avoid beans, pasta, fiber-rich grains, and foods high in fiber.
The day before the test:
- Have an early dinner (at least 14 hours before the test) consisting of rice and grilled or baked chicken or fish.
- You should fast for 12 hours before the breath test begins. This means you must not eat or drink anything other than water.
- You may continue taking your usual prescription medications with water. Please bring a list of all your prescription medications with you.
On the day of the test:
- You must not eat or drink anything in the morning.
- You may take your medications with a small amount of water. If you have diabetes that requires insulin or diabetes pills, ask your doctor if you should adjust your morning dose.
- Brush your teeth before the test.
- Before or during the test, do not eat, drink, chew gum or tobacco, smoke cigarettes, or use breath fresheners or candy.
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