Hydrogen Breath Test

What is a hydrogen breath test?

This is a test for bacterial overgrowth, or intolerances to lactose, fructose, or sucrose. Glucose is a sugar that will be broken down by bacteria if present in the small bowel with hydrogen or methane gas as a by-product.

Why is a hydrogen breath test performed?

The breath sample will be analyzed for hydrogen or methane content to determine if you are able to properly break down the lactose, fructose, or sucrose, or if you have bacterial overgrowth.

How do I prepare for a hydrogen breath test?

Prepping for a hydrogen breath test is not like a bowel prep for a colonoscopy. You will be provided with specific instructions for preparing for the test which will include, but isn’t limited to, eating a low carbohydrate diet for a couple of days.  The purpose of this diet is to avoid foods that may produce gas in the intestinal tract which could cause inaccurate test results.  You will also be given specific instructions regarding critical medications. 

Important Note:  Breath tests can be done any time before a colonoscopy prep, but not for four (4) weeks after a colonoscopy prep, or any test that requires a bowel prep.

What can I expect from a hydrogen breath test?

This test requires that you drink a solution of lactose, fructose, sucrose, or glucose in water. Lactose is the sugar found in milk and is normally broken down in the small bowel. Glucose is a sugar that will be broken down by bacteria if present in the small bowel with hydrogen as a by-product. Sucrose is a common sugar found in foods such as candy.

After drinking the solution, you will be asked to breathe into a plastic bag. Breath samples are obtained every 15 minutes for adults, and every 30 minutes for children. The breath sample will be analyzed for hydrogen content to determine if you are able to properly break down the lactose or sucrose, or if you have bacterial overgrowth.

Contact Information

The test is performed in the Gastrointestinal Physiology Laboratory of the Medical Procedures Unit and can be contacted by calling 734-936-9250, option 1.