SIBO Test: What It Is, How It’s Done, and When You Should Take It

What Is a SIBO Test?

A SIBO test measures the gases produced by bacteria in your small intestine after consuming a specific sugar solution. The two most common gases measured are hydrogen and methane, which are byproducts of bacterial fermentation. These gases are detected in your breath.

How the Test Works

1. You’ll drink a sugar solution (typically lactulose or glucose).

2. Breath samples are collected at regular intervals (usually every 15–20 minutes).

3. The samples are analyzed for levels of hydrogen and methane gases.

4. Higher levels than expected can indicate bacterial overgrowth in the small intestine.

The test is painless and non-invasive. You simply breathe into a collection tube.

What the Results Mean

• Hydrogen ↑ — may indicate bacterial overgrowth.

• Methane ↑ — may be associated with constipation-predominant SIBO.

• Normal results — suggests bacterial levels in the small intestine are within typical limits.

Interpreting results should be done by a healthcare provider experienced in digestive conditions.

When to Take a SIBO Test

You might consider taking a SIBO test if you have:

• Persistent bloating

• Gas after meals

• Abdominal discomfort

• Diarrhea, constipation, or alternating bowel habits

• Nutrient deficiencies or unexplained fatigue

A test helps distinguish SIBO from other digestive conditions with similar symptoms.

Preparing for the Test

Most protocols recommend:

• A specific preparatory diet for 24–48 hours before the test

• Avoiding certain supplements and medications

• Fasting the morning of the test

Follow your healthcare provider’s instructions carefully for accurate results.

Is It Worth It?

For many people with chronic symptoms, a SIBO test can be a useful tool to guide treatment and diet decisions. It’s not the only piece of the puzzle, but it can be an important one.