Hydrogen Breath Test

Hydrogen Breath Test

Hydrogen breath tests help to diagnose either intolerance to sugars or small intestinal bacterial overgrowth (SIBO).

The test measures how the amount of hydrogen present in your breath changes after you consume a sugar solution. There’s usually very little hydrogen in your breath. Having a higher level of it usually indicates a problem, either from sugar tolerance or bacterial growth in your small intestine.

To perform a hydrogen breath test, your doctor will start by having you gently blow into a bag to get an initial breath sample.

Next, they’ll have you drink solution containing different types of sugar. You’ll then breath into a bag every 15 to 20 minutes as your body digests the solution. After each breath, your doctor will use a syringe to empty the bag.

While hydrogen breath tests are fairly simple to do, they can take two to three hours, so you may want to bring a book to read in between breaths.

Your doctor will perform a hydrogen breath test if they suspect that you have an intolerance to a specific sugar or small intestinal bacterial overgrowth (SIBO).

Small intestinal bacterial overgrowth

SIBO refers to having an unusual amount of bacteria in your small intestine. This can cause many symptoms, including bloating, diarrhea, and malabsorption.

If you have SIBO, the bacteria in your small intestine will break down the sugar solution given during the hydrogen breath test. This results in hydrogen, which a hydrogen breath test will pick up.

Prior to hydrogen breath testing, the patient fasts for at least 12 hours. At the start of the test, the patient blows into and fills a balloon with a breath of air. The concentration of hydrogen is measured in a sample of breath removed from the balloon. The patient then ingests a small amount of the test sugar (lactose, sucrose, sorbitol, fructose, lactulose, etc. depending on the purpose of the test). Additional samples of breath are collected and analyzed for hydrogen every 15 minutes for up to five hours.