What Is a SIBO Breath Test?

The small intestinal bacterial overgrowth (SIBO) breath test is a noninvasive test that measures the amount of gases produced by bacteria in the small intestine.

Small intestinal bacterial overgrowth (SIBO) is a condition characterized by excessive bacteria in the small intestines leading to gut-related symptoms like bloating, diarrhea, and abdominal pain. While SIBO is not usually life threatening, it can significantly impact a person’s quality of life and make daily activities difficult.

The SIBO breath test involves consuming a sugar solution and then measuring the levels of hydrogen and methane in the breath at specific intervals. Having higher levels of these gases may indicate that a person has SIBO.

This article will give you an overview of the SIBO breath test, including what it is, how it works, what to expect before and during the test, and more.

Your doctor may use this breath test to detect the presence of excess bacteria in the small intestine (SIBO) or if they suspect you are intolerant to a certain type of sugar.

A doctor may order a SIBO breath test if you have symptoms of small intestinal bacterial overgrowth (SIBO), including:

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bloating
abdominal pain
diarrhea
nausea or vomiting
unintentional weight loss
malabsorption of nutrients

They may also recommend this test if you have had abdominal surgery or have any of the following conditions that can lead to SIBO:

inflammatory bowel disease (IBD), like Crohn’s disease
celiac disease
hypochlorhydria (low stomach acid)
sugar intolerance
gastroparesis (delayed stomach emptying)
diabetes
small bowel diverticula (a group of conditions that affect the digestive tract)

A SIBO breath test can be performed at a medical facility or at home, depending on the type of test being used.

SIBO breath test at home

At-home SIBO breath test kits are available both over the counter and with a prescription, depending on the kit. Over-the-counter kits can cost anywhere from $100 to $300, while prescription kits may be covered by medical insurance or government benefits, depending on your specific plan.

You should consider this type of test if you are unable to visit a doctor’s office or if you have mild to moderate symptoms of SIBO and have not previously been diagnosed or treated for the condition.

At a medical facility

You should consider taking the SIBO breath test at a medical facility if you have a history of gastrointestinal disorders or have previously received treatment for SIBO. The cost of this type of test can vary depending on the medical facility and your insurance plan, but it’s generally covered by medical insurance or government benefits.

The steps involved in the test may vary depending on whether you are taking an at-home test or having the test performed at a medical facility.

Before the test

Your doctor will give you instructions. They may advise you to follow a specific diet in the days leading up to the test. This can include avoiding foods or drinks containing high fiber, a lot of sugar, or alcohol because they can affect the results of the test.

You may also be advised to fast for 8 to 12 hours before the test. Your doctor will confirm with you when you should stop eating and drinking.

Additionally, you should refrain from certain medications like antibiotics or supplements that may affect the test outcomes. Consider speaking with your doctor before stopping any medications, as they may need to adjust your treatment plan or provide alternative medications.

During the test

At home

Your doctor will provide you with a kit that includes a sugar solution and a device for collecting breath samples.

First, you will consume the sugar solution provided in the test kit.
Collect breath samples at specific intervals using the collection tubes provided.
Once done, you will return the collected samples to the laboratory or your doctor for analysis.

At a facility

When you arrive, your doctor will collect a baseline breath sample before the test begins to establish your baseline level of hydrogen and methane.
They will then provide you with a sugar solution to consume. The sugar solution contains a specific type of sugar that the bacteria in the small intestine can ferment, producing hydrogen or methane gas.
Your doctor will collect breath samples at specific intervals, usually every 15 to 20 minutes for up to 3 hours.
The collected breath samples will be analyzed in a laboratory.

Some of the results you may receive after a SIBO breath test include :

Positive results: A rise in hydrogen gas of 20 parts per million (ppm), or 10 ppm in methane gas, above the baseline level in your breath within the first 2 hours of the test may indicate SIBO.
Negative results: No significant overgrowth of bacteria in the small intestine was discovered.

Some alternative tests for SIBO may include :

Stool testing: It’s less invasive than the breath test and can be used to detect SIBO by examining the levels of certain bacterial markers in your stool.
Intestinal biopsy: A biopsy is more invasive than a breath test and is typically reserved for cases where other tests have been inconclusive.
Serum antibody testing: This test is less invasive than the breath test, and it measures levels of antibodies against certain types of bacteria, which can indicate bacterial overgrowth in the small intestine.

Here are some frequently asked questions about SIBO breath tests:

Can a breath test detect SIBO?

Yes, a breath test can detect SIBO. It involves drinking a sugar solution and measuring the levels of hydrogen and methane gases in the breath over a set period.

How accurate is the breath test for SIBO?

The breath test is considered a reliable method for detecting SIBO, with a sensitivity and specificity of over 80%.

What does a SIBO breath test cost?

At-home test kits can cost anywhere from $100 to $300, while in-office tests can vary depending on the medical facility and your insurance plan.

What medications should you avoid before a SIBO breath test?

You should avoid medications that can interfere with the gut microbiota or the metabolism of the sugar solution, such as antibiotics, probiotics, antacids, and laxatives.

What does a positive SIBO breath test mean?

A positive SIBO breath test means an overgrowth of bacteria in the small intestine, which can lead to various gut-related symptoms.

A SIBO breath test is a noninvasive test used to identify the presence of small intestinal bacterial overgrowth (SIBO), a condition that can cause a variety of gut-related symptoms. This test can be performed at home or in a medical facility. Before this test, your doctor will give you instructions to follow regarding medication use, dietary restrictions, and other preparations to ensure the accuracy of the results.

Last medically reviewed on April 12, 2023

How we reviewed this article:

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Pimentel M, et al. (2020). ACG clinical guideline: Small intestinal bacterial overgrowth.
journals.lww.com/ajg/fulltext/2020/02000/acg_clinical_guideline__small_intestinal_bacterial.9.aspx
Rao C, et al. (2019). Small intestinal bacterial overgrowth: Clinical features and therapeutic management.
ncbi.nlm.nih.gov/pmc/articles/PMC6884350/
Rezaie A, et al. (2017). Hydrogen and methane-based breath testing in gastrointestinal disorders: The North American Consensus.
ncbi.nlm.nih.gov/pmc/articles/PMC5418558/

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