Hydrogen Breath Test

What is a Hydrogen Breath Test?

A hydrogen breath test is a quick, non-invasive procedure that measures hydrogen gas in your exhaled breath to assess how your body digests certain sugars. Abnormally high levels of hydrogen in the small intestine can indicate digestive problems such as sugar intolerances or bacterial overgrowth.

At Cooper Gastroenterology, we use hydrogen breath testing to help diagnose or rule out conditions including:

• Lactose intolerance and other sugar intolerances (fructose, sucrose)
• Small intestinal bacterial overgrowth (SIBO)
• Inflammatory bowel disease (IBD)

Your doctor may recommend a hydrogen breath test if you have:

• Abdominal pain
• Bloating
• Chronic digestive problems
• Frequent constipation or diarrhea
• Frequent flatulence

Preparing for a Hydrogen Breath Test

Preparation is key for accurate results and may begin up to a month before your scheduled test. Instructions will vary depending on your doctor’s goal, but may include:

• One month before: Stop antibiotics and probiotics.
• One week before: Avoid certain supplements, laxatives, fiber supplements, and antacids; smokers may be asked to quit.
• The day before: Eat a low-fiber diet, avoiding most grains, fruits, vegetables, beans, nuts, seeds, pasta, and most dairy products.
• Test day: Do not eat or drink anything (except water) for 12 hours before the test.

What to Expect During the Test

You will first breathe into a bag to measure baseline hydrogen levels.
You will then drink a sugar solution and provide breath samples every 15–30 minutes over several hours.
The test monitors how well your body breaks down sugars and checks for excessive bacterial activity in the small intestine.

Understanding Your Results

• Hydrogen levels are measured in parts per million (ppm).
• Any increase of more than 20 ppm above baseline is considered a positive result.
• Accurate results depend on following preparation instructions closely.