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.


      1. I took the SIBO test, first blow my methane baseline was too high (62ppm) waited 20 minutes second blow still too high (98ppm) They stopped the test said my numbers were too high. Can you explain what this means? Is this a positive or negative result or do I need to retest.
        Thank you

    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.

    1. I took the SIBO test, first blow said my methane baseline was too high (62ppm) waited 20 minutes and blew a 98ppm baseline. They stopped the test because my numbers were too high. Can you explain what this means? Is this a positive or negative result or do I need to retest.

  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!

  6. Hi,

    I started out with baseline 16 Methane and never went over 18. So I believe this is positive for Sibo but also for overproduction in the large bowel. I’ve been treating the Sibo with herbals for nine weeks now. Soon I will retest. My question is this – what kind of test result represents that Sibo is gone but that the large colon still needs to be treated? I’m afraid that I will keep overtreating Sibo and not actually deal with the large intestine issue

  7. Hello Todd,
    Thank you for this video! I’ve been trying to make sense of my first SIBO breath test before seeing my doctor next week and am grateful you offered a video specifically on methane. My doctor does not have the breadth of experience that you and other SIBO experts do so I am hoping to go in with as much information as I can.

    Might you be able to give a quick way to think about my results, specifically whether the results leans towards Methane Dominant SIBO (IMO), large bowel methane production or that it might indicate that I should have done the prep diet for longer? I have chronic/severe constipation so I also took Hydrogen Hydroxide right up until the night before. Not sure how that might have affected things and Genova was unhelpful when I called them. Could redo and stop two days before…

    My H2 was at 2 or 81 at 150 min and 38 at 180 min

    If it is a large intestine methane issue, and not formally SIBO, is the diet/protocol similar to methane dominant SIBO in terms of Dr Siebecker’s protocol with diet and the combo of Rifaximin and Neomycin?

    Thank you so much for considering

  8. Hi Todd, im in a very unusual situation where I cannot follow SIBO prep instructions thoroughly due to anxiety attacks from constiaption

    I’ve tested SIBO multiple times with negative results.

    Each time I was not able to complete the prep diet completely, took ox bile the days prior, discontinued PHGG (guar gum fiber) 5-6 days in advance, and had to take laxatives every night.

    I did however follow the fasting protocol correctly each time.

    Is it possible I’m still getting false negatives?

    low FODMAP diets don’t help me at all, if anything fiber helps me.

    1. SIBO test interpretation takes a bit of art and science to get the full value. I can’t tell you how many times a patient has come to me saying they had a negative SIBO test and when I look at it there was significant data (signs of slow transit, elevated methane on baseline – ie IMO – but no small bowel spike). There is the chance that it isn’t SIBO at all in which case I would be exploring other causes of constipation – motility disorders and fungal overgrowths to start.

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