What is SIBO Testing?

Levels of bacteria throughout the digestive tract

Testing for the presence of Small Intestinal Bacterial Overgrowth (SIBO), is done using a hydrogen-methane lactulose breath test. This is an inexpensive and non-invasive test that is done in the comfort of the patient's own home. It is imperative to test prior to treating SIBO, as testing identifies the type, severity, and general location of bacterial overgrowth, all of which factor into the treatment plan.

Our digestive system contains a plethora of bacteria, including some that produce hydrogen or methane. But under normal conditions, our bodies do not produce excessive levels of these gases. In the presence of bacterial overgrowth, carbohydrates are broken down in the small intestine and produce larger than normal quantities of hydrogen and/or methane. These gases expand the small intestine, leading to commonly experienced symptoms such as abdominal bloating, burping, flatulence, abdominal discomfort, and changes to bowel movements. The gases are then absorbed into the blood stream, where they travel to the lungs and are subsequently exhaled.  

Additional, detailed information regarding SIBO can be found at www.sibodoctors.ca

How Does the Test Work?

The lactulose breath test for SIBO involves a 24-hour preparation diet to eliminate foods that the bacteria feed on. The morning that the test is performed, 10 breath samples are completed, with the first sample being used as a baseline. The subsequent 9 samples are produced at 20-minute intervals following the ingestion of the lactulose. Lactulose is a carbohydrate that is not absorbed through the small intestine, and only bacteria have the enzymes available to break it down. Collection of breath samples every 20 minutes over a 3-hour period allows for the lactulose solution to travel through the entire length of the small intestine. The changes in hydrogen and methane concentrations in sequential breath samples will indicate the presence, type, significance and location of the overgrowth of bacteria in the small intestine.

What is the Difference Between Methane and Hydrogen Overgrowth?

Elevated levels of hydrogen are generally associated with a decrease in transit time, meaning it takes less time for food to travel through your digestive tract, leading to diarrhea. Elevated methane levels are generally associated with an increase in transit time, resulting in constipation. Treatment for the bacterial overgrowth will vary, depending on the levels and types of gases produced, as well as clinical symptoms.  

Currently, the most accurate, non-invasive method to test and diagnose SIBO, is using a 3-hour lactulose breath test.  SIBO can not be diagnosed with stool testing.  Some diagnostic testing laboratories may claim that SIBO can be detected using their stool testing methods, however this is false. Stool analysis provides no clinical value in regards to SIBO, as it primarily indicates what is happening in the large intestine, whereas SIBO occurs exclusively in the small intestine.