close   X

preparing for breath hydrogen test

on this page:

what is a breath hydrogen test?

A breath hydrogen test measures hydrogen in the breath. It is used to diagnose one of the following two conditions. These can cause abdominal (stomach) pain, cramping, bloating, gas or diarrhea.

  1. A condition in which dietary sugars are not digested normally, such as milk sugar (lactose), fruit sugar (fructose) or table sugar (sucrose).
  2. An overgrowth of bacteria in the small bowel, causing food and nutrients not to be absorbed properly. This can be caused by eating/drinking lactulose or glucose. Lactulose testing can give information about how long it takes food/drink to move through the small intestines to the colon.

how do I prepare my child for the test?

If any of these instructions are not followed, we will need to reschedule your test.

Starting 4 weeks before the test:

  • No antibiotics or probiotics. If prescribed antibiotics within four weeks of date of test, you must call to reschedule.

Starting 2 weeks before the test:

  • No probiotics.
  • No colonoscopy, barium enema or tests requiring bowel prep or cleansing.
  • If you have diabetes, talk to your doctor about how to take your medication the day of the test.

Starting 3 days before the test:

  • No Beano/Gas-X/activated charcoal or similar products.

Starting 24 hours before test:

foods you can eat:

  • Baked or broiled chicken, fish or turkey (salt and pepper only)
  • Clear chicken or beef broth (no vegetable pieces)
  • White bread (only)
  • Plain steamed white rice
  • Eggs
  • Water

do not eat these foods:

  • Sugars
  • Dairy
  • Oils
  • Butter
  • Processed foods
  • Deli meats
  • Condiments
  • Fruits or vegetables
  • Slowly absorbed carbohydrates like whole-grain bread, potato, beans, bran or fiber
  • Fiber supplements or laxatives
  • Soda, juice, tea, coffee, sports drinks, etc. (anything other than water)

12 hours before test (for example, 8:00 pm-8:00 am)

  • Do not eat or drink anything, except water.

Day of the test:

  • 2 hours before the test: Use small amount of water to brush your teeth and take medication.
  • 2 hours before and during the test, DO NOT:
    • Sleep
    • Exercise
    • Smoke or be exposed to second-hand smoke
    • Chew gum or tobacco
    • Eat hard candy

what happens during the test?

  • To get the breath sample, your child will blow into a balloon-type bag (or a face mask if they are small).
  • That breath sample will be put into an analyzer.
  • Your child will drink a small amount of a solution of lactulose, glucose, lactose, sucrose or fructose.
  • We’ll collect exhaled breaths and analyze them over the next 3 to 3.5 hours.

what happens after the test?

You may return to your usual diet and activity. A gastroenterologist will read the results and send them to your doctor.

what do I need to bring to the test?

Please bring your child’s bottle or favorite sippy cup. The test takes a few hours, so bring items that will help fill the time for you and your child.

where do I go when I arrive to Dayton Children’s?

This test is done at the specialty care center in Dayton (enter the parking lot at 860 Valley Street). Please arrive at least 20 minutes earlier than your scheduled appointment time to allow for check-in. You will check in at the front desk upon entering the building.

what if I need to reschedule or have questions?

  • To reschedule, call central scheduling:  937-641-4000 
  • For questions about the test, call pulmonary diagnostic lab: 937-641-4068


contact us

The pulmonary department’s triage nurses are available by phone at 937-641-3376 from 8:00 a.m. to 5:00 p.m. Monday through Friday to answer patient questions . After hours, call 937-641-3000 to reach the hospital’s operator and ask for the pulmonologist on call.