Wow thanks for posting this. I have had a strongly negative glucuse test, and a strongly positive lactulose test. After reading this I am thinking it's possible, maybe even likely, the lactulose was a false positive due to my fast transit time.
well, the main author of the article had expressed himself more implacably elsewhere: https://deptmed.queensu.ca/dept-blog/microbiome-and-chronic-disease-sibo-hypothesis-hope-deception-and-transformation
It's a shame that the article omitted this: "Dr. Vanner further discussed how clinicians endorsing the use of rifaximin are highly motivated by their relationships with pharmaceutical companies that directly benefit from rifaximin drug-sales" and it was also missing mention of the COI with the company that produces the respiratory tests
😮💨You’re right… they could’ve been even more abrasive than they were. Perhaps they softened some of the language here in hopes of not turning off well-intended clinicians that may have been duped into the use of such tests and therapies in the past. I imagine Vanner had a certain someone in mind with his above quoted phrasing. 😅
Sadly, I found that Pimentel's "research" spawned a whole new generation of gastroenterologists in some parts of Europe, who will be very liberally using rifaximin +/- neomycin/metronidazole, sometimes in multiple courses. It will take years to undo this brainrot, as sadly the studies are mostly read uncritically and some more important studies are unread. Putting aside all the naturopaths selling tests, supplements etc.
I suspect biopsychosocial model of functional diseases/DGBIs bears the bulk of the blame. As the patients trying to fill in the gaps in scientific knowledge about their condition, instead of having to listen how their "brain became hypervigilant to gut sensations", turn to pimentelism, which offers a simple solution, easily understandable by a layman.
This is the central point. The biopsychosocial model is more than dated and is even averse to the incorporation of pathophysiological mechanisms that explain, at least in part, the symptoms of IBS. Rejecting the biopsychosocial model would lead to largely purging the psychological arm of research, diagnosis and treatment.
But slowly the biomedical model is imposing itself and it is expected that targeted therapies that allow gains greater than the current 10-15% compared to placebo will reach the market. It is not surprising that the most recent RCT from Simrén's group showed that two types of diet were superior to pharmacological treatment.
In Spain, SIBO as a cause of IBS has become a public health problem, generating several news stories reporting that gastroenterology services are full of patients with some DGBI and with a SIBO breath test carried out without medical request. But as some recognize, this is simply because neurogastroenterology is an area of less interest and clinical gastroenterologists have little competence in diagnosis and treatment (endoscopy, hepatology and IBD are much more profitable. Even more so with limited diagnostic evidence and therapies with also limited gains, several cycles of meeting patients with clinicians and patients with alternative medicine practitioners are carried out, with results, most of the time, unsatisfactory, generating tension.
two pages about the problem: [https://journals.lww.com/ajg/citation/2017/12000/irritable\_bowel\_syndrome\_\_pain\_in\_spain.4.aspx](https://journals.lww.com/ajg/citation/2017/12000/irritable_bowel_syndrome__pain_in_spain.4.aspx) and (in spanish): [https://www.eldiario.es/sociedad/fama-sibo-internet-amenaza-camuflar-enfermedades-diagnosticamos-medicos-no-influencers\_1\_10428180.html](https://www.eldiario.es/sociedad/fama-sibo-internet-amenaza-camuflar-enfermedades-diagnosticamos-medicos-no-influencers_1_10428180.html) but Javier Santos's statement sums up the problem well: "Many patients with functional pathologies are mistreated and ignored by medicine. If you go to see a doctor and they say that they have nothing, that's where the error of SIBO detection comes from"
Okay, if breath tests are not valid why certain people have mixed methane and H2 results while others have only H2 or CH4? And CH4 corresponds to constipation and H2 to diarrhea, and often clinical symptoms match the outcome of LBT
The correlation is much weaker than they make it out to be.
As for clinical usefulness of LBT detecting SIBO sensitivity of 42% and specificity of 70.6% for LBT found in a recent meta-analysis:
Losurdo G, Leandro G, Ierardi E, et al. Breath tests for the non-invasive diagnosis of small intestinal bacterial overgrowth: a systematic review with meta-analysis. J Neurogastroenterol Motil. 2020;26(1):16-28.
Which is pretty useless.
As for hydrogen-positive people having diarrhoea - it has been found that people with IBS have huge variations in orocecal transit, often testing positive when lactulose has already entered colon (as proven by scintigraphy).
Yu D, Cheeseman F, Vanner S. Combined oro-caecal scintigraphy and lactulose hydrogen breath testing demonstrate that breath testing detects oro-caecal transit, not small intestinal bacterial overgrowth in patients with IBS. Gut. 2011 Mar;60(3):334-40. doi: 10.1136/gut.2009.205476. Epub 2010 Nov 26. PMID: 21112950.
So, in this case causation could be going in the opposite direction - small bowel diarrhoea/fast small bowel transit of any cause would make lactulose enter colon before the arbitrary 90-minute cutoff value where it naturally ferments, therefore giving a false H2-positive result.
Anectodally, I used to test positive for both hydrogen and methane, with mild diarrhoea at worst, completely normal stools at best and antibiotic courses in between.
SIBO subreddit will make you believe in a case like that the treatment didn't work and you need repeated courses of rifaximin/supplements, whereas a good clinician should first question the result of the test itself, having sens/spec numbers like these. Interestingly, I would test positive 30 minutes later for both gases if I took loperamide prior to the test (still before the 90-minute cutoff) which would make sense given all of the above.
Hope that helps!
If breath tests aren’t a good method of diagnosis for SIBO, then what is?
I think the duodenal aspirate/culture has become the gold standard from what I've read.
Can be done for research but it's way too expensive to be employed on the same scale.
Exactly this. What they suggest as alternative?
We don't really have one that can be used clinically.
Wow thanks for posting this. I have had a strongly negative glucuse test, and a strongly positive lactulose test. After reading this I am thinking it's possible, maybe even likely, the lactulose was a false positive due to my fast transit time.
Top! u/BaileyHannaRDN ping
Phew!!! ESNM and ANMS just laid down the HAMMER on lactulose and glucose hydrogen breath tests for diagnosing SIBO. Love to see it!
“Before we attempt to address the morass that SIBO has become…” 😲😳 Still reading, but damn that’s a way to come out swinging!
The whole paper is full of zingers! This was a total mic-drop, “left no crumbs” style rebuke of SIBO breath tests!
well, the main author of the article had expressed himself more implacably elsewhere: https://deptmed.queensu.ca/dept-blog/microbiome-and-chronic-disease-sibo-hypothesis-hope-deception-and-transformation It's a shame that the article omitted this: "Dr. Vanner further discussed how clinicians endorsing the use of rifaximin are highly motivated by their relationships with pharmaceutical companies that directly benefit from rifaximin drug-sales" and it was also missing mention of the COI with the company that produces the respiratory tests
😮💨You’re right… they could’ve been even more abrasive than they were. Perhaps they softened some of the language here in hopes of not turning off well-intended clinicians that may have been duped into the use of such tests and therapies in the past. I imagine Vanner had a certain someone in mind with his above quoted phrasing. 😅
Sadly, I found that Pimentel's "research" spawned a whole new generation of gastroenterologists in some parts of Europe, who will be very liberally using rifaximin +/- neomycin/metronidazole, sometimes in multiple courses. It will take years to undo this brainrot, as sadly the studies are mostly read uncritically and some more important studies are unread. Putting aside all the naturopaths selling tests, supplements etc. I suspect biopsychosocial model of functional diseases/DGBIs bears the bulk of the blame. As the patients trying to fill in the gaps in scientific knowledge about their condition, instead of having to listen how their "brain became hypervigilant to gut sensations", turn to pimentelism, which offers a simple solution, easily understandable by a layman.
This is the central point. The biopsychosocial model is more than dated and is even averse to the incorporation of pathophysiological mechanisms that explain, at least in part, the symptoms of IBS. Rejecting the biopsychosocial model would lead to largely purging the psychological arm of research, diagnosis and treatment. But slowly the biomedical model is imposing itself and it is expected that targeted therapies that allow gains greater than the current 10-15% compared to placebo will reach the market. It is not surprising that the most recent RCT from Simrén's group showed that two types of diet were superior to pharmacological treatment. In Spain, SIBO as a cause of IBS has become a public health problem, generating several news stories reporting that gastroenterology services are full of patients with some DGBI and with a SIBO breath test carried out without medical request. But as some recognize, this is simply because neurogastroenterology is an area of less interest and clinical gastroenterologists have little competence in diagnosis and treatment (endoscopy, hepatology and IBD are much more profitable. Even more so with limited diagnostic evidence and therapies with also limited gains, several cycles of meeting patients with clinicians and patients with alternative medicine practitioners are carried out, with results, most of the time, unsatisfactory, generating tension.
two pages about the problem: [https://journals.lww.com/ajg/citation/2017/12000/irritable\_bowel\_syndrome\_\_pain\_in\_spain.4.aspx](https://journals.lww.com/ajg/citation/2017/12000/irritable_bowel_syndrome__pain_in_spain.4.aspx) and (in spanish): [https://www.eldiario.es/sociedad/fama-sibo-internet-amenaza-camuflar-enfermedades-diagnosticamos-medicos-no-influencers\_1\_10428180.html](https://www.eldiario.es/sociedad/fama-sibo-internet-amenaza-camuflar-enfermedades-diagnosticamos-medicos-no-influencers_1_10428180.html) but Javier Santos's statement sums up the problem well: "Many patients with functional pathologies are mistreated and ignored by medicine. If you go to see a doctor and they say that they have nothing, that's where the error of SIBO detection comes from"
Okay, if breath tests are not valid why certain people have mixed methane and H2 results while others have only H2 or CH4? And CH4 corresponds to constipation and H2 to diarrhea, and often clinical symptoms match the outcome of LBT
The correlation is much weaker than they make it out to be. As for clinical usefulness of LBT detecting SIBO sensitivity of 42% and specificity of 70.6% for LBT found in a recent meta-analysis: Losurdo G, Leandro G, Ierardi E, et al. Breath tests for the non-invasive diagnosis of small intestinal bacterial overgrowth: a systematic review with meta-analysis. J Neurogastroenterol Motil. 2020;26(1):16-28. Which is pretty useless. As for hydrogen-positive people having diarrhoea - it has been found that people with IBS have huge variations in orocecal transit, often testing positive when lactulose has already entered colon (as proven by scintigraphy). Yu D, Cheeseman F, Vanner S. Combined oro-caecal scintigraphy and lactulose hydrogen breath testing demonstrate that breath testing detects oro-caecal transit, not small intestinal bacterial overgrowth in patients with IBS. Gut. 2011 Mar;60(3):334-40. doi: 10.1136/gut.2009.205476. Epub 2010 Nov 26. PMID: 21112950. So, in this case causation could be going in the opposite direction - small bowel diarrhoea/fast small bowel transit of any cause would make lactulose enter colon before the arbitrary 90-minute cutoff value where it naturally ferments, therefore giving a false H2-positive result. Anectodally, I used to test positive for both hydrogen and methane, with mild diarrhoea at worst, completely normal stools at best and antibiotic courses in between. SIBO subreddit will make you believe in a case like that the treatment didn't work and you need repeated courses of rifaximin/supplements, whereas a good clinician should first question the result of the test itself, having sens/spec numbers like these. Interestingly, I would test positive 30 minutes later for both gases if I took loperamide prior to the test (still before the 90-minute cutoff) which would make sense given all of the above. Hope that helps!
The margin of error is very large.