New Testing Options for IBS & SIBO
How IBS is Currently Diagnosed
IBS is a functional gut-brain disorder, meaning it affects the function of the gut and not the structure. This means there are no structural abnormalities that would show up during many tests, including colonoscopies and CT scans. These tests are typically done to look for abnormalities that would be indicative of other conditions, as many IBS symptoms overlap with those of other conditions.
IBS is diagnosed via the Rome IV diagnostic criteria (more on the diagnosis here). This diagnosis can be made before ruling out other conditions, but many doctors prefer to start ruling out other conditions before the diagnosis is made. Typically, celiac disease and IBD will be screened for via blood tests, a stool test may be done to check for an infection, and breath tests may be done to look for SIBO or specific carbohydrate enzyme deficiencies. From there, other testing may be done.
The diagnostic process for IBS is not the same for everyone. There is no exact standard
Blood Test for IBS
A newer test that has been successful in identifying post-infectious IBS is IBS Smart, which tests for two biomarkers for IBS: anti-CdtB and anti-vinculin. The test IBSchek blood test also tests for the same biomarkers.
When there is an infection, anti-CdtB antibodies are released as part of the immune response, then anti-vinculin is produced. Anti-vinculin attacks a protein in the gut that leads to nerve damage and dysmotility, the main issues with IBS that can lead to hypersensitivity and altered bowel habits.
What’s your poop personality? Find out here!
This blood test can be helpful in confirming a diagnosis that has been made, as well as the source of the diagnosis, and may be helpful in determining a diagnosis for those who present with diarrhea or mixed symptoms.
What this can’t do is confirm an IBS diagnosis that was not caused by infection. Note that the more we learn about IBS, the more we will be able to understand the causes. We know food-borne illness is one of the top causes, especially for IBS-D and mixed types, and we also know that there are other potential causes like chronic stress, antibiotic use, illness, or treatment for certain illnesses. We know there could be a genetic factor and a hormonal factor to the cause of IBS. So the IBS Smart test may not identify these causes.
A big value of this test is that it could save money and time by confirming a diagnosis and not needing additional testing. It has been validated through this study by Cedars Sinai.
Does this mean that IBS may be simplified to only post-infectious IBS? Until we better understand and can determine the “why” for IBS caused by other reasons, I don’t think we will see IBS simplify to this point. As we do better understand what may be going on in the body from these other causes and are able to identify the pathophysiology (a long work for “why”) of the symptoms and altered function, we may see IBS break up into other classifications or more specific metrics for the IBS diagnosis.
From the results of the studies that led to and validated these blood tests, treatments can be targeted based on the results, and preventative methods can be used to prevent worsened symptoms in the future with food-borne illness.
Coming Soon
There is currently research going by Dr. Mark Pimentel’s team at Cedars Sinai that looks at the different types of SIBO overlapping with what we have known to be IBS, as well as specific microbiome therapies that are tailored for IBS. This research should be published soon, which could lead to more tailored treatment options and a better understanding of this disorder.
Breath Testing for SIBO
Over the last few years, a new type of overgrowth within the SIBO umbrella has been identified: intestinal methanogenic overgrowth. Since methanogens are archaea instead of bacteria, this is actually shortened to IMO (intestinal methanogen overgrowth), versus SIBO for hydrogen overgrowth. For simplicity, we typically refer to both as SIBO. In the last year, another type of overgrowth has been added to the testing panel for SIBO, called hydrogen sulfide overgrowth. This would be referred to as excess hydrogen sulfide.
There is now a breath test available called Trio Smart that tests for all three types of overgrowth. This test can be ordered by your provider and taken at home. Learn more about the types of SIBO and what the standards of testing are here!
Are you frustrated with your IBS symptoms? Do you desire to be confident in your food choices? Do you want to have a healthier relationship with your body and diet? Are you ready to take control of your IBS?
