What is SIBO?
SIBO stands for Small Intestine Bacterial Overgrowth and occurs when normal bacteria end up living in excessive numbers in the small intestine, causing havoc. It is estimated that on average 60% of all Irritable Bowel Syndrome is actually caused by SIBO, with up to 84% of IBS patients having SIBO in one study. You can read more about SIBO in our What You Need To Know About SIBO article. In today's article we look at how to get tested for SIBO and when you should consider re-testing for it.
Who Should Get Tested For SIBO?
If you have IBS, chronic tummy troubles, coeliac disease, crohns disease or ulcerative colitis, you might like to consider being tested for SIBO. There are a range of treatment options available for SIBO, and identifying its presence opens the options of relief from its associated symptoms. The good news is there are a couple of different ways to be tested, which we explore below.
How To Get Tested For SIBO
SIBO Breath Test
A SIBO breath test is non-invasive, easy to do, can be done at home or in-clinic and is the most common method to test for SIBO. It works by measuring hydrogen and/or methane on the breath at specific intervals of time, over a period of time, after a person drinks a sugar solution (lactulose or glucose). You can take this free online quiz to determine the likelihood of SIBO being present before ordering a test.
A person is considered positive for hydrogen SIBO if they have an increase of 20ppm (parts per million) over the lowest preceding value within the first 100 minutes.
A person is considered positive for methane SIBO if they have an increase of 12ppm over the lowest preceding value within the first 100 minutes.
If the rise occurs during 100-120 minutes for either hydrogen or methane, this is considered a borderline result.
Some patients experience high baseline levels. Some doctors interpret this as a positive test result. With methane SIBO, this is particularly true since a high baseline and an early rise is a standard methane pattern. Improper preparation can be indicated when gas levels fall after an elevated baseline and continue to reduce or remain low during the first two hours.
Preparing for the SIBO Breath Test
The following needs to be adhered to in order for the SIBO breath test results to be reliable.
One month prior: No colonoscopies, barium studies, colonics, or antibiotic use.
One week prior: Stop all probiotics, probiotic-containing products (Eg. Yogurt, fermented foods), herbal antimicrobials.
One day prior: Stop laxatives, digestive aids (eg. Enzymes, hydrochloric acid), non-essential supplements. Follow prep diet and 12-hour fast.
SIBO Breath Test Prep Diet and 12-Hour Fast
A simple diet that is low in fermentable carbohydrates and fibre must be followed 24 hours prior to the commencement of testing. If a person is constipated, they are required to follow the diet for 48 hours.
Each laboratory has slightly different allowed foods, but they generally include eggs, white fish, chicken, turkey, white rice, hard aged cheese, eggs, clear meat broth (made without bones and vegetables), olive oil and coconut oil for cooking, salt and pepper for seasoning, weak black tea and coffee and plain water. If you aren't provided with dietary instructions prior to testing, it is recommended you contact the facility to confirm what they require so that you don't inadvertently skew the results.
In addition to the diet, a 12-hour fast is required immediately prior to testing to allow the food to transit through the small intestine and leave it relatively empty.
The 24 hours prior to testing might look like this:
7 am: Scrambled eggs with a cup of weak black tea or coffee.
10 am: Cup of warm meat broth.
1 pm: Grilled fillet of fish with jasmine or basmati rice.
4 pm: Cup of soup made from meat broth and jasmine or basmati rice.
7 pm: Grilled chicken with jasmine or basmati rice.
7.30 pm - 7.30 am: No food. Water only.
6.30 am until end of test: No smoking (or second-hand smoke), no exercising, no sleeping. You can brush your teeth as normal.
7.30 am - 10.30 am: SIBO breath test. Small amounts of plain water can be sipped during the testing window.
10.30 am onwards: Resume eating as normal.
"Doing a SIBO breath test gave me piece of mind. Getting a SIBO diagnosis meant I finally knew what was going wrong with my gut. My practitioner had a plan in place and we commence treatment immediately. At long last, I was on the road to recovery from my debilitating gut symptoms.
The SIBO breath test has given people all around the world the opportunity to get answers as to what is going on in their gut.
Easy to do
Relatively quick to do (3 hours)
Get results quickly
Most common SIBO diagnostic test
Can diagnose both hydrogen and methane SIBO
Not suitable for people who can't blow into a tube
Can't diagnose Hydrogen Sulfide SIBO
Sugar solution may temporarily worsen symptoms
Lactulose is a prescription item in the US
Glucose only measures SIBO in first 3 feet of small intestine
Requires proper preparation, fasting for 12 hours and 3 hours to do the test
May provide false negative and false positive results in some patients due to improper preparation or other conditions affecting gut transit time
An aspirate can be taken from the second part of the small intestine. This can be performed by an endoscopy in-clinic, generally under anaesthesia or sedation. A sample is taken and the culture is grown to determine what bacteria are present.
This test is invasive, costly and difficult to find because it requires a highly skilled medical professional to undertake the test. For these reasons, it is not commonly used.
It can also produce false-negative results if the bacterial overgrowth is further down the small intestine, where the sample hasn't come from, if the sample size was too small, or if the bacteria that was collected can't be cultured.
Preparing for the Jejunal Aspirate
Your doctor's office will have specific instructions for preparing for a jejunal aspirate, but they may be similar to the SIBO breath test prep.
Considered gold standard by some practitioners
Requires sedation or anaesthetic
Requires a gastroenterologist to perform procedure
Greater risks as a medical procedure
Can produce false negative and positives results
What Doesn't Test For SIBO?
Stool testing can be very informative about a person's large intestine health and their broader GI health. It can show if there are imbalances or pathogenic organisms. However, it cannot diagnose SIBO as by its very nature, the stool test cannot determine where the bacterial overgrowth is occurring. The overgrowth could be from the large intestine, the small intestine or both.
If it is not possible for a person to undertake a breath test, such as for very young children who cannot blow into a tube, this can be a good indicative starting point until a breath test can be taken.
Urine Organic Acids Test
Bacteria and fungus produce organic acids which are excreted in your urine. A urine organic acids test measures the level of organic acids that you have excreted, giving you an indication that you may have a yeast or bacterial overgrowth somewhere in your body.
However, like the stool test, it is unable to pinpoint exactly where the overgrowth is occurring, and for this reason, cannot be used to definitively diagnose SIBO.
The Future Of SIBO Testing
Researchers and breath test manufacturers are working on a commercially suitable test for Hydrogen Sulfide SIBO, which should be available in the coming years. There may also be exciting developments with the use of smart devices, which are swallowed and can take samples along the entire length of the small intestine tract.
Should You Re-Test For SIBO?
If, after a round of treatment, you don't feel noticeably improved, then it may be worth considering re-testing for SIBO. This can provide your practitioner with useful information, such as whether the treatment was effective, which gas(es) is still present and what treatments should be utilised next.
However, it is important to remember that a person is more than their test results. How you feel is more important than what a test result says. If you feel better, that is a more important metric to hold onto. I have had many SIBO coaching clients who have tested positive for SIBO, yet feel remarkably better than when they first started treatment.
If you found this article on how to get tested for SIBO helpful, I would love to hear your thoughts. Simply leave a comment in the comments section below.
"I have chronic, relapsing SIBO. I listen to my body and let it guide me with symptoms. I re-test for SIBO on occasion when I want information on whether I have hydrogen, methane or both, what my gas levels are like, and what treatment I need to consider. I let my body tell me how I am actually feeling, not a test result.
Get help for your SIBO journey
SIBO Coaching Sessions provide you with tailored and personalised support. Your SIBO coach, Rebecca Coomes, has helped thousands of people all around the world to feel supported, listened to and cared for while providing them with the lifestyle, emotional and nutrition tools to live well with SIBO.