Testing for Small Intestine Bacterial Overgrowth is an absolute must. With nearly 100 other diseases carrying overlapping symptoms with SIBO, getting an accurate diagnosis is nearly impossible without a positive SIBO test.
SIBO is largely diagnosed through the hydrogen breath test.
How the test works
SIBO breath tests work by feeding the bacteria that make up Small Intestine Bacterial Overgrowth and then monitoring their growth over the course of the standard transit time, or time it takes food to move through the digestive system.
The SIBO breath test consists of consuming a sugary substance and then monitoring the gases released in the breath for 2-3 hours. The sugary substance is often lactulose or glucose. Lactulose is not digestible by humans. This means when lactulose is consumed it is able to travel through the digestive system undigested therefore remaining available to feed any bacteria making up Small Intestine Bacterial Overgrowth. As the bacteria in SIBO eat the lactulose or glucose they grow and release gases called methane and hydrogen. These gases are then absorbed through the intestinal wall, into the blood stream, and transported to the lungs where they are expelled into the air when breathed out. The test is then designed to catch these gases by breathing through a small apparatus that collects the gases in test tubes. The test measures the gases released by the body over the course of the standard transit time, testing every 20-30 minute for the total 2-3 hours. (Transit time is the amount of time it takes for food to leave your stomach and travel to your large intestine, roughly 3 hours.) This allows the test to show where the SIBO bacteria is located in the small intestine. As a spike in hydrogen/methane gas at 40 minutes after lactulose show the SIBO is relatively high in the digestive system, near the stomach, while a spike at 90 minutes shows the SIBO is closer to the colon. Higher levels of gases show higher levels of SIBO. Knowing where the SIBO is located and how severe the SIBO is allows for better treatment options.
The breath tests are usually performed in the morning after a nightly fast and a 1-2 day preparation diet. These specifications allow for better baseline readings and test results which more accurately show the location and severity of the SIBO.
Summary of the breath test:
- The breath test is performed in the morning before consuming food or beverages.
- Preparing for the test includes a preparation diet (1-2 days), fasting before the test (8 hours or overnight).
- To start the test a sample is taken as a baseline reading.
- Next, lactulose is consumed.
- Then, samples are collected every 20-30 minutes for two to three hours.
- Return the samples to the lab within the timeframe provided.
Click here to see an example of a testing procedure.
What is included in the test kit
- Lactulose or glucose powder to be mixed with water and consumed during the test.
- A breathing apparatus used to collect the gas expelled by the lungs and transferred into test tubes for measurement.
- Several test tubes to collect gas through the breathing apparatus.
- Labels
- Instructions
- Bubble wrap or protective wrap to protect the test tubes
- Requisition form, surveys
What to expect
SIBO tests usually require a special preparation diet for 1-2 days prior to the test. Some doctors follow the recommended diet included in the test kit instructions, while some doctors recommend one of the stricter phases of the SIBO diets. The purpose of the preparation diet is to decrease any SIBO flares so the first measurement of the test provides an accurate baseline reading. Additional instructions like not smoking, avoiding laxatives and vitamin C may be required. Instructions like waiting 4 weeks after antibiotics or anti-fungals need the approval of your doctor. Many SIBO doctors will perform a SIBO test within 2-3 days of antibiotic treatment to learn about the success of the treatment.
The test is performed in the morning after a fasting period.
Turn around times for results are usually 5-7 days. Shipping and testing increase the time it takes from ordering the test to knowing results to about 1-3 weeks.
Where is the test performed
The test is often performed at home, but is available through some participating labs. You can order test kits through different labs, or get them from your doctor. For home testing, the completed test kit is sent to a lab for reading. Results are then sent directly to your SIBO doctor for interpretation.
Downsides of the Test
Time Consuming: The test usually takes 3 hours to perform with a preparation diet 1-2 days before. The test is most often performed in the morning so it can be a burden to your schedule.
Triggers A SIBO Flare: The entire purpose of the test is to measure the SIBO bacteria. In order to accomplish this the SIBO bacteria must be fed, this means performing a positive SIBO test WILL cause a SIBO flare.
Results Are Not Standardized: There is no official standard for SIBO test results. This means the results that one doctor consider to be a positive SIBO test may not be a positive SIBO test in the opinion of another doctor. There are generally accepted positive and negative values but test interpretation does vary between doctors. While this can be discouraging, the best way to account for this is to use a treating doctor who is well versed in current SIBO research and who has treated many patients before you.
Three Hour Breath Test Labs *
SIBO breath tests come in 2 hour tests and three hour test. Three hour tests are considered more reliable and more indicative of the condition of the digestive system. All of the SIBO test labs listed below have a 3 hour breath test available. Test prices range from $150-$350.
- True Health Labs, $309, Direct patient ordering available
- SIBO Testing Center, In Lab testing provided for $229, At home test kits are $159
- SIBO Center Lab NUNM, SIBO kit $180
- Neurovanna
- Genova Diagnostics
- Direct Labs $259-$359, Direct patient ordering available
- Breath Trackers/QuinTron
- Biohealth Laboratory
- Aerodiagnostics, $200-$300, International Testing Available
*List of labs provided by SIBOinfo.com, test prices as of April 2018.
For more international options please see SIBOinfo.com.
I am not an affiliate with any of the SIBO breath test labs. I have used both QuinTron and Genova Diagnostics for my personal testing and have had great experiences with these companies. In general Genova is a bit more expensive but is easy to use, reliable, and very comprehensive. Genova also offers comprehensive stool analysis for determining if other imbalances are part of your gut dysbiosis.
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