5 Common SIBO Testing Mistakes

SIBO is fast becoming recognised as one of the main causes of IBS in over 60% of people.  With that in mind, I wanted to write a quick blog to explain the importance of getting tested in the right way.  I can’t tell you how often I see clients who have come to me having done a SIBO test elsewhere that has been conducted with several mistakes.

So here are 5 common SIBO testing mistakes to check out when you are going for a SIBO test:

1. Is the SIBO test testing for both methane and hydrogen gas?

The herbal anti-microbial supplements used for methane are different from those used for hydrogen, so it is important that the test looks at both gases.

2. Is the SIBO test using lactulose, glucose or fructose to detect SIBO?

10g lactulose is my go to substrate to use in testing because it picks up the majority of the small intestine.  If a client does a SIBO test and it comes back negative, but I have a strong suspicion of SIBO I will then test glucose next, as glucose picks up SIBO in the upper part of the digestive tract.  A glucose test alone won’t necessarily tell us what is going on in that lower part of the small intestine.

I now also use fructose to test for SIBO as not all bacteria eat lactulose. If a client can afford it, I prefer to test all 3 sugars, fructose, lactulose and glucose, as lactulose captures the distal part of the small intestine, whereas glucose only captures the proximal (upper) part.

3. Is the SIBO test a 3 hour test or a 2 hour test?

It is important to see what is going on in that third hour as in the third hour we expect to see a rise in gas as the substrate hits the large intestine and the bacteria there ferment it.  However, if someone has a flat line across the whole of the test with no rise in that third hour, it is possible that they actually have a third type of SIBO, hydrogen sulphide SIBO, which again requires different supplements and even a different diet.  I myself had a flatline SIBO test which I was told by the lab I used to use was negative.  It turned out that I had hydrogen sulphide SIBO which had gone undiagnosed.  I want to prevent you from having the same false test readings.

4. Is the machine calibrated regularly and is carbon dioxide gas measured in the breath samples to check whether they are valid samples or not?

This can be important in determining the accuracy of the test as many mistakes can be made when collecting your breath samples.

5. Have you followed the correct preparation ahead of the SIBO test?

I’ve seen clients be given foods in their prep diets that can skew the accuracy of the test.  I have even seen clients who haven’t been told about the importance of doing a prep diet before testing, what supplements to avoid, etc.  All of these factors can affect the accuracy of your test results.  It is important that whoever you are working with gives you clear and accurate prep guidelines.

If you suspect that SIBO might be behind your IBS, I hope that this blog will help prevent you from wasting your time and resources on sub-standard testing methods and coming away with false negative or false positive test results.

Or read my blog on IBS and SIBO here

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