Breath Testing for Lactose Intolerance and for Other Carbohydrate Intolerances

What Is Lactose Intolerance?

Lactose intolerance is the inability to digest lactose, the sugar found in milk. It causes cramping, bloating, gas, or diarrhea any time dairy products are consumed. Lactose intolerance occurs due to the body's lack of lactase, an enzyme normally produced by the small intestine that is needed to digest lactose.

What Happens During the Hydrogen Breath Test?

During the hydrogen breath test, which takes about 2 hours, you will be asked to drink a lactose-containing beverage. The beverage may cause cramping, bloating, gas, or diarrhea.

How Do I Prepare for the Hydrogen Breath Test?

Before the hydrogen breath test, tell your doctor if:

You have just had a colonoscopy; if so, you will need to wait a few weeks after the colonoscopy before this test can be performed.

You are pregnant, have a lung or heart condition, have any diseases, or if you are allergic to any medications

Other Guidelines for the Hydrogen Breath Test

Do not eat or drink anything (including water) for at least 8 hours before the hydrogen breath test. If you need to take medicine, take only with a small sip of water 8 hours before the procedure.

Do not take any antibiotics for 2-4 weeks before the test. Take only the medications approved by your doctor before the procedure. Do not discontinue any medication without first consulting with your primary or referring doctor.

Do not chew gum on the day of the test.

Your doctor may have other recommendations in addition to, or instead of, the ones listed above. Ask your doctor to provide you with written instructions prior to your test.

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