SIBO: Methane SIBO test results

Hey folks this is Todd Mansfield I’m here from Byron herbalist and today we’re going to be talking about SIBO breath test, specifically methane dominant SIBO, and some different patterns that you might see as well as the approach that you might take to reading a methane SIBO breath test. We will also cover the implications of large bowel methane production in certain cases of methane dominant SIBO

When you’re using a SIBO breath test to assess for methane dominant SIBO and it comes back with methane production you are generally going to see one of three patterns.

Pattern One – Methane SIBO breath test

The first one is classic methane dominant SIBO starting with low baseline methane. Then there is a steep increase in methane production before the 90 minute mark. Different labs will use different cut-off values. Some use and increase of 12 parts per million or more. Personally I use an increase of 10 parts per million or more as I do want to treat bacterial overgrowth if it is present. 

Pattern Two – Methane SIBO breath test

The second pattern you may see are similar the results from the graph below taken from a scientific journal. The paper is called Elevated Methane Levels in Small Intestinal Bacterial Overgrowth Suggest Delayed Small Bowel and Colonic Transit. So below we have a graph showing high baseline methane which someone made a comment on the blog post saying that it may not be methane SIBO but high methane production in the large bowel. 

SIBO breath test showing methane dominant SIBO
Image taken from: Elevated Methane Levels in Small Intestinal Bacterial Overgrowth Suggest Delayed Small Bowel and Colonic Transit

As long as the test prep diet was followed – if a patient is significantly constipated then they need to follow the test prep diet longer – there is still a significant rise in methane over baseline. As you can see it goes from just below 120ppm to about 160ppm and then it stays along the same line and then again there is a pretty significant rise before the 90 minute mark. As long as the test prep diet was followed for the proper amount of time I would still consider this methane dominant SIBO and I would treat the small bowel.

Pattern Three – Methane SIBO breath test

This brings me to the third methane positive result that you might find with a SIBO breath test. This is when you start with a high baseline methane and  it stays high without the spike in methane. This presentation isn’t technically methane dominant SIBO as far as we know. We are  thinking more along the lines of large bowel methane production. 

This is why it’s so important to assess the large bowel at the same time that we are assessing the small bowel. Here I will use a DNA based stool test that will give assess the complete microbiome of the large bowel. We used to use Ubiome, they have since gone out of business, so companies like Thryve have really stepped up to fill in the niche. Here in Australia you can use Microba which will give you the bacterial composition of the large bowel as well.

If a SIBO breath test had high baseline methane and didn’t have a significant spike of methane (or even if it did) I would be thinking that the large bowel is involved in methane production as well. And here we turn to the large bowel stool test results from a patient that did have methane dominant SIBO and high baseline methane. Here we have an overgrowth of the genus Methanobrevibacter, members of this genus produce methane, representing 1.18% of the bacterial makeup of this patient’s large bowel. This is most likely a Methanobrevibacter smithii overgrowth which is the most commonly found methane-producing microbe in SIBO, and also in the large bowel in humans. An overgrowth turning up at 1.18% is orders of magnitude higher than optimal. 

Treat the SIBO first

If this patient did have methane dominant SIBO, seen as a significant increase in methane on a SIBO breath test, we would want to be treating the small bowel which is our top priority. Once we’ve cleared methane producing microbes in the small bowel then we can move onto the large bowel. Treating high methane, whether it’s in the small bowel or the large bowel, will help with constipation, gut transit time and many other symptoms associated with methane SIBO.

If you are struggling with constipation, you think you might have methane SIBO then don’t hesitate to get in touch and we will see if we can help you out.

Do you have any experiences with contipation, methane SIBO or other digestive troubles? Share your thoughts below!

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  1. Positive sibo test. High methane at baseline. Stayed high no peak <81 the whole time. So treat sibo first? Antibiotics? Then large bowel with what? Thanks

    1. Hi Melissa,

      I would interpret a high baseline methane as colonic methane production although that can be argued. 81 is on the higher end. Different herbs can be used, some doctors recommend combined antibiotics and I go for a herb, prebiotic, probiotic combo for the most part.


    2. Here are my Methane #’s: 13 (baseline), 11 (20 min), <2 (40 min), <2 (60 min), 3 (90 min), 4 (120 min), 7 (150 min), 8 (180 min)
      Dr wants me on a super restrictive biphasic SIBO diet with Allimed and GI Detox…is this necessary?

  2. Hi Todd.
    Methane positive.
    Baseline methane was 20, then 23,23,17,21 then 25 at 2hrs.
    H2 was 1,1,3,1,1 and 7
    So no rise, but higher methane level than it should be.
    Do you think Colonic here or also Sibo?

  3. I had a Lactulose breath test. Starting Methane was 6. That was the highest it was. Mayo said it was a negative test. My ND said positive. My FMD isn’t sure. Dr. Pimental- I believe said 3ppm. Do you follow him at all? Thoughts? I can’t seem to get an answer.

  4. Hi Todd !
    I got my SIBO test with lactulose results.
    I’m constant for 80 minutes. Then at 100 minutes I’m at 110 ppm, 120 minutes 123ppm. At 140 it’s get lower 107ppm then lower again at 160minutes 71ppm. And finally it’s increase again at 180minutes 123ppm.
    I did all the preparation really carefully.
    I have SIBO right?
    I’m really disappointed.
    Thank you for your help.
    Best regards Tania.

  5. Hi there. Just received 3-hour SIBO test results, as follows:
    H2 – <2 baseline; 81 @ 40, 60, 90, 120, 150 and 180 minutes
    Any thoughts?
    I don’t know what >81 means or why an absolute number isn’t reported.
    I am a 59-year-old female if that is relevant.
    Thank you!

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