SIBO (Small Intestine Bacterial Overgrowth) 2.25 Hour Lactulose Test #900-C



Lab Tests Plus – SIBO Tests from Lab Tests Plus on Vimeo.

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.

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:
Constipation Malnutrition
Irritable Bowel Syndrome (IBS)
Leaky Gut Syndrome
Chronic Fatigue Syndrome
Acid Reflux

Test #900-C – Lactulose challenge option for higher specificity in the upper small intestine. The 2.25 Hour Method reduces the likelihood of false positive results. It is guided by the findings of the 2017 North American Journal of Gastroenterology: Hydrogen and Methane based breath testing in Gastrointestinal Disorders: The North American Consensus.

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 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.

Refer to test kit instructions for more specifics on how to do the collections and detailed instructions on medications, circumstances, underlying medical conditions, supplements, diet, etc. that may affect the results of the test.


√ Lab Test
√ Doctor’s Review of Test Results
√ Doctor’s Recommended Course of Action

NOTE: This test is not available to residents of New York or Maryland. Any orders originating from the state of New York, Rhode Island or Maryland will automatically be canceled. Any samples originating from the state of New York or Maryland will be discarded.


Lab Test
√ Doctor’s Review of Test Results
√ Doctor’s Recommended Course of Action

This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure or prevent any disease. Always consult with your professional health care provider if you are taking any medication.