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March 14, 2023

SIBO Testing 101: A Complete Guide to The Top 3 SIBO Tests

Written By
Dr. Jaime Cloyd ND
Medically Reviewed by
Updated On
January 14, 2025

Small intestinal bacterial overgrowth (SIBO), often used as a blanket term for SIBO and intestinal methanogen overgrowth (IMO), refers to the presence of an increased number of bacteria in the small intestine. IMO, previously called methane-SIBO, involves the presence of methane-producing microorganisms (archaea) in the small or large intestines.

SIBO breath tests are tools that may help in assessing SIBO and IMO by measuring hydrogen and methane gases produced by intestinal microorganisms over 2-3 hours. Hydrogen sulfide gas is also associated with SIBO, and recent advancements in testing now allow for the assessment of hydrogen sulfide-SIBO. This article will discuss the SIBO breath tests available to order through Rupa Health.

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What is SIBO Testing?

SIBO breath testing is a noninvasive alternative to small intestinal culture that may help in assessing SIBO and IMO. A SIBO breath test is performed the morning after a patient follows a specific preparatory diet and overnight fast. The test begins with the patient collecting a baseline breath sample and drinking a water mixture containing either glucose or lactulose. The patient then continues collecting breath samples at timed intervals for the test duration, lasting 2-3 hours.

Bacteria and archaea in the gastrointestinal (GI) tract ferment carbohydrates, producing hydrogen, methane, and hydrogen sulfide gases. These gases diffuse into the bloodstream and are exhaled through the lungs. Elevations of gas levels during the SIBO breath test may indicate the presence of bacteria and/or methanogens in the GI tract. Per the North American Consensus, a test is considered positive if at least one of the following criteria is met (1, 2):

  • Hydrogen-SIBO: hydrogen levels rise at least 20 ppm from baseline within the first 90 minutes of the test
  • IMO: methane level is at least 10 ppm at any time point during the test
  • Hydrogen sulfide-SIBO: hydrogen sulfide level is at least 3 ppm at any time point during the test

There is no universal standard SIBO breath test. Glucose and lactulose breath tests both offer their own benefits. Glucose is absorbed within the first three feet of the small intestine; the advantage of a glucose breath test is that it may help limit the number of false positive test results, and it can accurately assess overgrowth within the proximal small intestine. Humans cannot digest or absorb lactulose; the advantage of a lactulose breath test is that it can assess overgrowth in the distal portions of the small intestine, which is thought to be more common. (1)

Which Patients is SIBO Testing Best Used For?

SIBO has been associated with many digestive and non-digestive symptoms and medical conditions. Over two-thirds of patients with diagnosed SIBO report digestive symptoms, including bloating, abdominal discomfort, belching, flatulence, indigestion, constipation, and diarrhea. Symptoms can vary in frequency, duration, and severity. Irritable bowel syndrome (IBS) is a functional bowel disorder diagnosed when abdominal discomfort and irregular bowel movements are present for at least six months. IBS and SIBO/IMO symptoms overlap; data reveal that nearly 80% of patients with IBS have underlying SIBO contributing to their symptoms. (3, 4)

SIBO testing can be beneficial for other patients, too, as SIBO has been associated with a variety of other conditions, including inflammatory bowel disease (IBD), rosacea, restless legs syndrome (RLS), pancreatitis, hypothyroidism, Parkinson's disease (PD), diabetes, and coronary artery disease. Additionally, people who use proton pump inhibitors (PPIs) and opioids may have a higher risk for developing SIBO/IMO. (3)

Rupa Health's Top 3 Popular SIBO Test Overview

Here is an overview of Rupa Health's Top 3 Most Popular SIBO Test in our reference guide:

1. SIBO Test from Genova Diagnostics

What Does This Test Measure?

Genova offers a SIBO 2-Hour and 3-Hour lactulose breath test, which both measure hydrogen and methane gas levels in breath samples collected by the patient over a two- or three-hour testing period.

What Makes This Test Popular?

Lactulose breath tests depict SIBO and IMO located in the proximal and distal portions of the small intestine. The SIBO 3-Hour test is the only three-hour SIBO breath test available to order through Rupa Health.

When Should You Consider This Test?

Ordering providers must have prescriptive rights to order Genova's SIBO breath tests. Lactulose breath tests should not be ordered for anyone with a documented lactulose allergy.

The SIBO 3-Hour test is preferred for patients with chronic constipation or slowed intestinal motility. A three-hour breath test is also preferred to assess for colonic IMO.

Sign Up to Order the SIBO Breath Tests from Genova Diagnostics🧪

Trio-smart from Gemelli Biotech

What Does This Test Measure?

The trio-smart breath test measures hydrogen, methane, and hydrogen sulfide gases produced by bacteria and methanogens in the gastrointestinal tract over a two-hour testing period.

What Makes This Test Popular?

trio-smart is the most comprehensive SIBO breath test because it is the only test capable of measuring hydrogen sulfide gas levels. trio-smart offers both glucose and lactulose versions of the test.

When Should You Consider This Test?

The trio-smart test should be considered for patients you are interested in assessing for hydrogen-SIBO, hydrogen sulfide-SIBO, and IMO. Patients unable to perform the lactulose breath test due to allergy can take the glucose breath test.

Sign Up to Order the trio-smart SIBO Breath Test from Gemelli Biotech🧪

SIBO/IMO Test from Commonwealth Diagnostics International

What Does This Test Measure?

Commonwealth Diagnostics International (CDI) offers a glucose and a lactulose SIBO/IMO breath test. Both tests measure hydrogen and methane gas levels over a 2-hour and 15-minute time period.

What Makes This Test Popular?

Ordering physicians can order either a glucose or lactulose breath test, depending on their testing preferences and needs. Given the test duration, the lactulose breath test can assess for IMO in the beginning portion of the large intestine. CDI's SIBO breath tests are the least expensive SIBO testing option offered through Rupa Health.

When Should You Consider This Test?

If cost is an inhibiting factor for a patient, CDI's breath tests are good SIBO testing options for assessing hydrogen-SIBO and IMO. The SIBO/IMO glucose breath test can be ordered for patients with lactulose allergy.

Sign Up to Order the SIBO/IMO Breath Tests from Commonwealth Diagnostics International🧪

Summary

SIBO breath tests act as convenient at-home testing aids to assess small intestinal bacterial overgrowth and intestinal methanogen overgrowth. Depending on your clinical needs, various breath tests may serve you better than others. SIBO breath tests primarily differ between the testing period's duration and the substrate included in the test kit. All SIBO breath tests measure hydrogen and methane gas levels derived from intestinal bacteria and methanogens. The trio-smart breath test is the only test that measures hydrogen sulfide gas levels. A comparison table for all SIBO breath tests available to order through Rupa Health can be viewed here.

The information in this article is designed for educational purposes only and is not intended to be a substitute for informed medical advice or care. This information should not be used to diagnose or treat any health problems or illnesses without consulting a doctor. Consult with a health care practitioner before relying on any information in this article or on this website.

Learn more

Lab Tests in This Article

1. Rezaie, A., Buresi, M., Lembo, A., et al. (2017). Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus. The American Journal of Gastroenterology, 112(5), 775–784. https://doi.org/10.1038/ajg.2017.46

2. Breath Testing. Trio-smart. https://www.triosmartbreath.com/breathtesting

3. Rao, S.S., & Bhagatwala, J. (2019). Small Intestinal Bacterial Overgrowth. Clinical and Translational Gastroenterology, 10(10):p e00078. https://doi.org/10.14309/ctg.0000000000000078

4. Takakura, W., & Pimentel, M. (2020). Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome – An Update. Frontiers in Psychiatry, 11. https://doi.org/10.3389/fpsyt.2020.00664

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