Small Intestinal Bacterial Overgrowth (SIBO) Breath Testing
Glucose and lactulose breath test methods for assessing numerous health disorders…


SIBO (Small Intestinal Bacterial Overgrowth) is a condition in which abnormally large numbers of bacteria – the types that are normally found in the large intestine – are present in the small intestine. When not functioning properly, the migrating motor complex (MMC) fails to effectively sweep intestinal contents into the colon during periods of fasting. Once in the small intestine, these bacteria proliferate and feed off carbohydrates from food, creating fermentation gases, specifically methane and hydrogen. SIBO breath testing measures these gases.

  • Non-invasive breath collection
  • Convenient interpretive guidance right on the test result
  • Complimentary interpretive support available from experienced clinicians

SIBO can be a cause of many health problems, including diarrhea, abdominal pain, and protein/fat malabsorption. In recent years, there has been renewed interest in SIBO since it has now been implicated in the pathophysiology of certain diseases previously not classically associated with overgrowth. The World Journal of Gastroenterology claims a definitive association between irritable bowel syndrome (IBS) and SIBO, suggesting that SIBO be excluded before diagnosing a patient with IBS.

Common conditions associated with SIBO:
  • Nausea
  • Flatulence
  • Diarrhea
  • Constipation Malnutrition
  • Irritable Bowel Syndrome (IBS)
  • Leaky Gut Syndrome
  • Chronic Fatigue Syndrome
  • Acid Reflux
  • Rosacea
  • Fibromyalgia
  • GERD

The Hydrogen/Methane breath test is a reliable and convenient method to help in assessing and classifying dysbiosis and SIBO.

BioHealth provides clinicians with high-quality SIBO testing services:


North American Consensus – 2.25-Hour Method

  • Test #900-C – Lactulose challenge option to detect bacterial overgrowth in the distal small intestine
  • Test #901-C – Glucose challenge option for higher specificity in the upper small intestine
  • Test #910-C – Discounted glucose/lactulose combo available at discount. For details on the glucose-lactulose combo, view this PDF.

Traditional (Slow Transit/HIgh Retention) – 3-Hour Method

  • Test #900 – Lactulose challenge option to detect bacterial overgrowth in the distal small intestine
  • Test #901 – Glucose challenge option for higher specificity in the upper small intestine
  • Test #910 – Discounted glucose/lactulose combo available at discount. For details on the glucose-lactulose combo, view this PDF.

Fructose Malabsorption Test

  • Test #920 – Fructose challenge to detect malabsorption in colon
  • Test #911-C – Discounted glucose/lactulose/fructose combo


  • Test Fee: Available to clinicians.
  • To order test kits, proceed to SIBO Order Page (Dropship only).
  • Specimen: 10 Breath samples using the EasySampler™ Breath Test Kit (for each of the test types). This patented breath-collection kit allows for patients to collect samples unsupervised and mail their samples to the laboratory for analysis.
  • Turnaround Time: 2-3 business days
  • CPT Codes: Hydrogen – 91065, Methane – 91065


Providing a Convenient Assessment of Bacterial Overgrowth with a Simple Breath Test

What Is This Test For?
The Small Intestine Bacterial Overgrowth (SIBO) Breath Test provides valuable information in the diagnosis of small bowel overgrowth of bacteria, otherwise known as SIBO. Small Intestine Bacterial Overgrowth describes a condition in which bacteria from the large intestine have migrated to the small intestine. SIBO can also occur when bacteria native to the small intestine have simply overgrown. Using a breath test to diagnose SIBO is simple, non-invasive and inexpensive. A breath test specifies which gases are present, in addition to the location and severity of bacterial overgrowth.

With lactulose, there is greater ability to diagnose overgrowth in the distal end of the small intestine, which is thought to be most common. With the glucose challenge, absorption occurs faster so the test more accurately diagnoses proximal overgrowth, which is considered more specific to the bacteria of concern. While clinicians and researchers alike debate which method is superior for SIBO testing, we know that the patient is best served by doing both.

The large intestine (colon) has a quantity and variety of bacteria different from those of the small intestine.The small intestine houses approximately 10,000 bacteria per milliliter of fluid, as compared to the large intestine which houses approximately one trillion bacteria per milliliter of fluid. The primary function of the colonic bacteria is the fermentation of non-digestible carbohydrates, resulting in the formation of short chain fatty acids which stimulate epithelial growth and differentiation in the colonic epithelium.

The primary functions of the small intestine are those of digestion and absorption of nutrients from our food. The bacteria in our small intestine aid in digestion and absorption, produce valuable nutrients, support gut immunity and protect us from other invading organisms. Through enzymes produced by the pancreas and along the brush border of the small intestine, carbohydrates are digested and their nutrients absorbed into general circulation. Bile from the liver and gall bladder digest fats and promote the peristaltic action of the small intestine (migrating motor complex) that moves food through to be further digested and absorbed along the length of the small intestine.

Why is SIBO a Problem?
The misplacement of normal colonic bacteria into the small intestine results in fermentation, rather than the normal digestion and absorption that are the primary functions of the small intestine. When carbohydrates ferment rather than digest, hydrogen and methane can be produced in measurable quantities. The process of fermentation rather than digestion creates a host of symptoms that can be difficult to treat effectively without diagnosing and addressing the root cause.

What Does This SIBO Breath Test Measure?
Hydrogen – Bacteria produce hydrogen through the process of fermentation of unabsorbed carbohydrates. A small amount of hydrogen is normally produced from limited amounts of unabsorbed carbohydrate reaching the colon. However, large amounts of hydrogen may be produced if there is malabsorption of carbohydrates and/or bacterial

Sample SIBO Report

overgrowth in the small intestine, allowing a larger amount of hydrogen to reach the colon. The hydrogen produced by the bacteria is absorbed through the wall of the small and large intestines. The hydrogen-containing blood travels to the lungs, where the hydrogen is released and exhaled in the breath. Elevated hydrogen levels tend to be associated with IBS-D (diarrhea) and faster transit times.

Methane – About 15 percent to 30 percent of people have gut flora that contain Methanobrevibacter smithii, which converts four atoms of hydrogen into one molecule of methane. These subjects may not exhale much hydrogen in the breath test despite having SIBO or carbohydrate malabsorption, as excess hydrogen produced as a result of fermentation is converted into methane. Elevated methane levels tend to be associated with IBS-C (constipation) and slower transit times. Both hydrogen and methane are produced by bacteria and are not a normal product of human metabolism. Too much hydrogen, methane or both is a positive test for bacterial overgrowth of the small intestine.

How Is The Test Performed?
1. There is a 24-hour preparation phase before the test is performed.
2. In the first 12 hours, dietary restrictions must be followed. The patient must avoid all grains, fruit in all its forms, sugar in all its forms, dairy in all its forms, vegetables, nuts and seeds, alcohol and beans. Refer to the test kit instructions for permitted foods.
3. The last 12 hours is a fasting period. Only water can be consumed.
4. Included in the test kit is a packet of lactulose or glucose that is to be mixed with 8 ounces of water then set aside.
5. Collect a baseline breath sample before consuming the glucose or lactulose mixture.
6. After collecting the baseline breath sample, drink the mixture.
7. Fifteen minutes after consuming the lactulose or glucose mixture, breath sample #2 is collected. Breath samples are collected every 15 minutes thereafter until all tubes are used.
8. Please refer to test kit instructions for more specifics on how to perform the collections and detailed instructions on medications, circumstances, underlying medical conditions, supplements, diet, etc. that may affect the results of the test.

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