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SIBO SERIES PART 2: The Science (and Art) of SIBO Testing

We know that SIBO is hugely underdiagnosed and potentially responsible for up to 85% of IBS cases; people who are told that there is nothing identifiably wrong with them. But how can this be? Why is SIBO so commonly missed or overlooked? A big part of the problem has to do with SIBO testing; who to test, when to test, how to test and most importantly how to interpret the SIBO breath test results. This is an area of SIBO research that has changed quite a bit in the last few years and one that many practitioners haven’t kept pace with. For a lot of IBS sufferers, a proper diagnosis is so critical, both psychologically and for informing effective treatment to overcome the horrible symptoms that…

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  Why your SIBO Breath Test Result May Not be Reliable

SIBO breath tests play a pivotal role in diagnosing and understanding Small Intestinal Bacterial Overgrowth (SIBO). During a SIBO breath test, patients drink a sugar solution that feeds bad bacteria in the small intestine. If SIBO is present, the bacteria in the small intestine ferment the solution, releasing gasses like hydrogen, methane, or hydrogen sulfide. These gasses are absorbed into the bloodstream and eventually exhaled... Currently, there’s a gap in medical knowledge about SIBO. Most practitioners aren’t taught in med school how to correctly interpret a SIBO breath test, and often practices vary–meaning that one practitioner may give you a negative result while another may give you a positive one.

 SIBO Test Overview

The Lactulose Breath Test for SIBO is designed to take a three-hour picture of how the bacteria in your intestinal system are functioning. When bacteria digest food, they produce gas. These gasses go through your intestinal walls into your bloodstream, end up in the lungs, and you breathe them out. The breath samples that are collected get tested for the levels of Hydrogen and Methane being exhaled. These levels tell your doctor where bacteria are fermenting in your intestinal system, and how much gas they are creating. This will enable your healthcare professionals to help you get rid of your bacteria and the symptoms they cause. Learn more about SIBO testing.

 SIBO Test – All Your Questions Answered

SIBO is confusing. You’ve heard that this condition—Small Intestinal Bacterial Overgrowth—might be contributing to your IBS or other symptoms, but you’re not sure how to go about addressing it. There are several different tests for SIBO out there and it’s hard to know which one is best for you. It can also be difficult to get your head around how SIBO tests work.

 What’s the Most Accurate SIBO Breath Test for Diagnosis?

There are two types of SIBO breath tests: lactulose breath tests and glucose breath tests. The lactulose test is generally more popular, but the data indicate it’s not as accurate. SIBO breath testing can be helpful, but it has limitations. Of the SIBO breath tests, the glucose breath test is best. However, a well-trained clinician can responsibly use a lactulose test.

Articles of Interest

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

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.

Your SIBO Breath Test Report and What It Says About Your Gut Health

Whilst methane isn’t used in the SIBO diagnosis, it can indicate an imbalance in gut microbiome. Low levels of methane are common in healthy individuals, however high levels of methane (>10ppm) have been associated with constipation and bloating. Methane isn’t produced by bacteria, but by methanogens, which are a type of archaea and use the hydrogen produced by bacterial fermentation to produce methane.

Breath testing for small intestinal bacterial overgrowth: maximizing test accuracy

The diagnosis of small intestinal bacterial overgrowth (SIBO) has increased considerably owing to a growing recognition of its association with common bowel symptoms including chronic diarrhea, bloating, abdominal distention, and the irritable bowel syndrome. Ideally, an accurate and objective diagnosis of SIBO should be established before initiating antibiotic treatment. Unfortunately, no perfect test exists for the diagnosis of SIBO. The current gold standard, small-bowel aspiration and quantitative culture, is limited by its high cost, invasive nature, lack of standardization, sampling error, and need for dedicated infrastructure. Although not without shortcomings, hydrogen breath testing provides the simplest noninvasive and widely available diagnostic modality for suspected SIBO.

Breath tests and irritable bowel syndrome

Breath tests are non-invasive tests and can detect H2 and CH4 gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath. These tests are used in the diagnosis of carbohydrate malabsorption, small intestinal bacterial overgrowth, and for measuring the orocecal transit time. Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome (IBS)-type symptoms such as diarrhea and/or constipation, bloating, excess flatulence, headaches and lack of energy.

Breath Tests for the Non-invasive Diagnosis of Small Intestinal Bacterial Overgrowth: A Systematic Review With Meta-analysis

Small intestinal bacterial overgrowth (SIBO) diagnosis is usually based on non-invasive breath tests (BTs), namely lactulose BT (LBT) and glucose BT (GBT). However, divergent opinions and problems of parameter standardization are still controversial aspects.

How to Interpret Hydrogen Breath Tests

Hydrogen breath tests using various substrates like glucose, lactulose, lactose and fructose are being used more and more to diagnose small intestinal bacterial overgrowth (SIBO) and lactose or fructose malabsorption. Though quantitative culture of jejunal aspirate is considered as gold standard for the diagnosis of SIBO, hydrogen breath tests, in spite of their low sensitivity, are popular for their non-invasiveness. Glucose hydrogen breath test is more acceptable for the diagnosis of SIBO as conventionally accepted double-peak criterion on lactulose hydrogen breath test is very insensitive and recently described early-peak criterion is often false positive.

How to Test for Small Intestinal Bacterial Overgrowth (SIBO)

There are two types of breath tests: One uses glucose and the other lactulose. Of the two, the glucose test seems to be better. But both are often inaccurate. The sensitivity and specificity of the tests range from 44% to 83%. Breath testing for small intestinal bacterial overgrowth: maximizing test accuracy. The test can also produce false negatives. That's often because of gastroparesis (slow emptying of the stomach). In addition, there's no consensus on how best to perform the test. Nor is there agreement on exactly what amounts of gas should be present for a positive result. Still, the simplicity and safety of the test make it a popular way to test for SIBO.

Pros and Cons of Breath Testing for Small Intestinal Bacterial Overgrowth and Intestinal Methanogen Overgrowth

Like any clinical test, breath testing has inherent strengths and limitations, and results must be interpreted with consideration of the clinical context and influencing factors.

Understanding Our Tests: Hydrogen-Methane Breath Testing to Diagnose Small Intestinal Bacterial Overgrowth

There is increasing appreciation that small intestinal bacterial overgrowth (SIBO) drives many common gastrointestinal symptoms, including diarrhea, bloating, and abdominal pain. Breath testing via measurement of exhaled hydrogen and methane gases following ingestion of a readily metabolized carbohydrate has become an important noninvasive testing paradigm to help diagnose SIBO. However, because of a number of physiological and technical considerations, how and when to use breath testing in the diagnosis of SIBO remains a nuanced clinical decision.

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.

Why Should I Consider Breath Testing?

IBS is a complex disorder and there is no cure. Up to 90% of IBS sufferers identify food as a trigger for their symptoms and yet the incidence of medically diagnosed food allergy or food chemical sensitivity in the population is very low – less than 2%. Despite their prevalence, FODMAP intolerance and SIBO often remains undiagnosed.