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Symptoms Quiz

Is It Really IBS?

Take a short quiz to find out if an antibody blood test for IBS is recommended for you.


While irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) share some symptoms, they are completely different illnesses. 

Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease (IBD) is a long-term health issue that causes swelling and sores in the gastrointestinal tract.

IBD causes your immune system to think that food in the intestine is not supposed to be there. The body then attacks the cells of the bowels, causing inflammation and ulcerations


There are two main types of inflammatory bowel disease (IBD): ulcerative colitis and Crohn’s disease


Symptoms of IBD, like symptoms of IBS, include diarrhea and abdominal pain; however, in addition to these, IBD symptoms also include rectal bleeding, joint pain, eye irritation, and rashes


While there is currently no known cure for IBD, there are various immunosuppressants to help manage the symptoms of IBD.

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Here is an excellent patient guide to IBD published by the American Gastroenterological Society in Clinical Gastroenterology and Hepatology.

How Do You Diagnose
Inflammatory Bowel Disease (IBD)?

There are various ways your doctor might want to test for IBD. Diagnostic procedures might include stool tests, blood tests, and often more invasive endoscopic procedures like a colonoscopy


Your doctor will want to know where in your body the inflammation is occurring and will want to get a clear understanding of the state of your gastrointestinal tract. 


There are two types of IBD that can be diagnosed. Crohn’s disease is inflammation or ulceration located throughout the GI tract, and ulcerative colitis is inflammation found in the large bowel or rectum. 


Both types of IBD have their own symptoms that guide your doctor towards the most appropriate tests.

Ulcerative Colitis


  • Diarrhea

  • Fever & fatigue

  • Abdominal pain and cramping

  • Blood in your stool

  • Reduced appetite

  • Unintended weight loss

  • Red, swollen eyes

Crohn's Disease 

  • Cramps/belly pain (often in the lower right side)

  • Diarrhea

  • Weight loss

  • Bleeding

  • Skin rash

  • Arthritis (painful, swollen joints)

  • Fatigue

Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome, or IBS, is a health issue found in your intestines. It causes persistent abdominal pain, cramping, gas, bloating, and change in stool - some combination of chronic diarrhea and constipation. If you are suffering from these symptoms, you're not alone. Nearly 40 million Americans suffer from IBS

There are three types of IBS: diarrhea-predominant (IBS-D), constipation-predominant (IBS-C), and mixed-type (IBS-M, where diarrhea and constipation both persist). IBS does not cause lasting harm to the bowels and does not lead to cancer; however, it can severely impair you physically and emotionally. 

Food poisoning is the leading known cause of IBS, accounting for at least 60% of all diarrheal IBS cases. The path from food poisoning to IBS has to do with a toxin called Cytolethal Distending Toxin B, or CdtB for short. The most common bacteria that cause food poisoning like Shigella, Campylobacter, Salmonella, and E. coli. release the toxin CdtB into your body. 


When a toxin like CdtB enters your body, your immune system fights back with an antibody - in this case, your body creates anti-CdtB. CdtB looks in some ways like vinculin, a naturally occurring protein in your body that is critical in healthy gut function. Because CdtB and vinculin can look alike, your body can think it needs to fight back against vinculin, at which point it starts producing another antibody, anti-vinculin. 


The production of anti-vinculin is an autoimmune response and leads to gut nerve damage and improper functioning of the Interstitial Cells of Cajal (ICC) and Migrating Motor Complexes (MMC). When these do not function properly, your gut microbiome is disrupted. Your gut microbiome is composed of billions of bacteria in your gut that, when balanced, keep your gut healthy.

This disruption ultimately results in irritable bowel syndrome (IBS).

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Here is an excellent patient guide to IBS published by the American Gastroenterological Society​.

How Do You Diagnose Irritable
Bowel Syndrome (IBS)?

Traditionally, IBS was an exclusionary diagnosis, meaning other diseases - especially IBD - had to be ruled out in order to diagnose IBS. Alternatively, an antibody blood test can diagnose IBS more directly


Irritable bowel syndrome can be accurately ruled in with a simple, doctor-ordered antibody blood test.  The test measures the levels of two antibodies, anti-CdtB and anti-vinculin, known to be elevated in the blood of the majority of patients experiencing IBS with diarrheal symptoms. If either antibody is elevated, a confident IBS diagnosis can be made. 


A positive result on the test also indicates that the root cause of your IBS was an instance of food poisoning (gastroenteritis) that has led to a disruption in your gut microbiome. This can guide your healthcare provider to therapies that treat your microbiome, like FDA-approved antibiotics and low-fermentation diets. 


If your antibody blood test result is not positive, your doctor may want to conduct other tests to diagnose your symptoms.


The American College of Gastroenterology's Clinical Guidelines for the Management of IBS suggest "a positive diagnostic strategy" (ruling in IBS) as compared to "a diagnostic strategy of exclusion" (ruling out other diseases) " improve time to initiate appropriate therapy....and to improve cost-effectiveness."

What Is ibs-smart?

ibs-smart is the only licensed, patented test that can measure validated biomarkers, anti-CdtB and anti-vinculin,  in your blood that indicate IBS with 96% - 100% positive predictive value. Further, the test is over 90% specific in differentiating IBS from other diarrheal diseases like IBD. While IBS and IBD can co-exist, IBD itself does not lead to the elevation of these antibody biomarkers.

By accurately diagnosing your IBS and identifying the cause (a microbiome disruption caused by an infection), ibs-smart™ can
expedite your path to treatment and prevent years of potentially unnecessary procedures like colonoscopies.

You can order ibs-smart without an appointment online through our online prescriber service or download a patient-doctor discussion guide to take to your next doctor’s appointment.

Order ibs-smart Online.

No appointment necessary

You can work with a doctor online to order ibs-smart, if it’s right for you.

The online prescriber service includes:

  • A symptoms evaluation by a doctor

  • Clear and actionable results emailed directly to you

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Prefer to work with your healthcare provider instead? Download the ibs-smart discussion guide and educational materials here

Woman with IBS

Post-Infectious IBS

A significant volume of research shows a clear link between food poisoning

and irritable bowel

syndrome (IBS).

Woman with IBS pain

Diarrhea & IBS

Chronic diarrhea can indicate disorders, such as inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS).

Woman with IBS


While what causes SIBO is an excess of bacteria, there are many conditions that can lead to SIBO like irritable bowel syndrome.

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