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How to Test for IBS at Home: Step-by-Step Guide

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How to Test for IBS at Home: Step-by-Step Guide

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Key Takeaways

  • Irritable bowel syndrome (IBS) is a chronic gastrointestinal condition characterized by abdominal pain associated with bowel movements. It may also include symptoms such as diarrhea, constipation, and bloating.
  • There are currently two at-home tests for IBS: IBSchek and IBS-Smart.
  • At-home IBS tests measure the amount of antibodies (anti-CtdB and anti-vinculin) in your blood and can be diagnostic of IBS-D or IBS-M caused by a gastrointestinal infection.

Irritable bowel syndrome (IBS) is a common digestive condition that affects approximately 4.4 to 4.8 percent of people in the United States, United Kingdom, and Canada. It is more common in women and in people younger than 50 years of age.

The most common symptom of IBS is abdominal pain related to bowel movements. Other common symptoms of IBS include diarrhea, constipation, bloating, and the feeling that you haven’t completed a bowel movement after going to the bathroom.

In recent years, at-home tests for IBS have become available. This article reviews how to test for IBS at home, which tests are available, and what to do if you receive a positive IBS result.

If you receive a positive IBS result, consider booking a virtual appointment with a registered dietitian at Nourish. They can help you determine a nutrition plan tailored to your individual needs.

What is Irritable Bowel Syndrome (IBS)?

IBS is a disorder of gut-brain interaction, meaning that it occurs due to miscommunication between the gut and the brain.

This miscommunication can cause your gut to be extra sensitive and changes how your gut muscles contract.

IBS is characterized by recurrent abdominal pain associated with bowel movements, changes in frequency of bowel movements and changes in the appearance of stool.

With IBS, these symptoms are present without any visible damage to your gastrointestinal tract.

There are four subtypes of IBS: IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), IBS with mixed bowel habits (IBS-M) and IBS unclassified (IBS-U), which is when a person’s IBS does not fall into any of the other categories. 

Benefits of Testing for IBS

In the past, IBS was a diagnosis of exclusion, meaning it was diagnosed once all other possible causes had been ruled out.

However, the American College of Gastroenterology clinical guidelines for the management of IBS recommend using a positive diagnostic strategy to diagnose IBS.

The benefit of testing for IBS directly is that it can provide evidence for a diagnosis much more quickly than if a person does several other tests to rule out other conditions.

This may reduce the amount of time that a person must wait to receive treatment for IBS. 

Do Home IBS Tests Exist?

Currently, there are two at-home blood tests that can diagnose certain types of IBS.

IBSchek and IBS-Smart measure antibodies associated with IBD-D and IBD-M when a person has had a recent gastrointestinal infection, such as food poisoning.

The antibodies measured are anti-cytolethal distending toxin B (anti-CdtB) and anti-vinculin.

These biomarkers are not commonly elevated in people with IBS-C, so these test kits can only be used to diagnose IBS-D and IBS-M that have developed after a gastrointestinal infection.

Although at-home tests are available, they must be ordered by a licensed physician.

Are Home IBS Tests Accurate?

According to a validation study of close to 3,000 patients, the IBSchek test is over 90 percent specific and about 40 percent sensitive.

This means that negative results are accurate about 90 percent of the time, while positive results are accurate about 40 percent of the time.

According to a study looking at the ability of the IBS-Smart test to differentiate between IBS-D and inflammatory bowel disease (IBD), when both anti-CdtB and anti-vinculin were positive, there was a 98 percent probability that a person had IBS-D. 

Overall, the study results show that the tests can reliably diagnose IBS-D and IBS-M that are associated with a prior gastrointestinal infection.

However, they are not able to diagnose IBS-C, nor can they diagnose IBS-D and IBS-M that are not related to a prior gastrointestinal infection.

Types of Home Tests for IBS

There are two home tests for IBS available: IBSchek and IBS-Smart.


The IBSchek test is a non-invasive, at-home blood test. There are two possible test results for the IBSchek test. 

“Supportive” test results mean that either antibody (anti-CdtB or anti-vinculin) levels are greater than the reference level. This suggests a greater likelihood of having IBS-D or IBS-M and that the IBS may be due to a previous gastrointestinal infection.

“Not Supportive” test results mean that both antibodies (anti-CdtB or anti-vinculin) levels are below the reference level. This does not exclude IBS-D or IBS-M, but it shows that further investigations are needed to determine what is causing a patient’s gastrointestinal symptoms.


IBS-Smart is a simple, at-home blood test. You can work with your own doctor or one of the IBS-Smart online doctors to obtain an order for the IBS-Smart test.

Once you have submitted the order form, you will receive a kit for your blood to be professionally drawn. Once drawn, your doctor or phlebotomist will send the blood sample to the IBS-Smart lab.

Test results for IBS-Smart are available by email or from your doctor within seven days of your sample being received.

Elevated anti-CdtB indicates that a recent case of gastrointestinal infection has caused the IBS, while elevated anti-vinculin indicates that autoimmunity (when the immune system mistakenly attacks healthy cells, tissues, and organs) is present. 

If both anti-CdtB and anti-vinculin are not elevated, IBS was not likely caused by infection, and further investigation into the cause of symptoms should be initiated.


Home IBS Test vs. Diagnostic Lab Tests

Currently, there are no diagnostic lab tests that specifically test for IBS.

However, several diagnostic lab tests may be done to rule out other conditions as the cause of symptoms.

They include tests that can identify celiac disease, inflammatory bowel disease, and infectious diseases.

Home IBS tests may provide a benefit over diagnostic lab tests used to rule out other conditions because they can provide a positive result for IBS. However, at-home IBS tests must still be ordered by a physician, as only a physician can make a diagnosis of IBS.

What Can You Do After a Positive IBS Result?

Once you’ve received a positive IBS result, it’s important to talk to your doctor about your treatment options. There are many available treatments for IBS, including:

  • Changes to what you eat (such as eating more fiber or following the low FODMAP diet.)
  • Increasing physical activity.
  • Managing stress levels.
  • Getting enough sleep.
  • Medications.
  • Cognitive behavioral therapy.
  • Gut directed hypnotherapy.

Each person is unique and may require a combination of treatments to manage IBS.

If you want to try the low FODMAP diet to manage your IBS symptoms, consider booking a virtual appointment with a registered dietitian at Nourish. They can help you understand the different components of the low FODMAP diet and ensure you get all the nutrients you need.

Other Ways to Diagnose IBS

IBS is typically diagnosed after a review of symptoms, medical history, and family history. A physical exam is also typically performed. In some cases, the following tests may also be used to diagnose IBS:

  • Blood tests (to check for other health conditions such as celiac disease.)
  • Stool tests (to check for infections or other health conditions such as inflammatory bowel disease.)
  • Breath tests (to check for small intestinal bacterial overgrowth or lactose intolerance.)
  • Upper GI endoscopy with biopsy (to check for celiac disease.)
  • Colonoscopy (to check for colon cancer and inflammatory bowel disease.)

Your doctor may use a combination of the above tests to diagnose IBS.

When to See a Medical Provider About Your IBS Symptoms

If IBS is negatively impacting your day-to-day life, it’s important to see a medical provider who can provide information regarding treatment options. In addition, if you have symptoms such as unexplained weight loss, blood in your stool, a hard lump or swelling in your abdomen, shortness of breath, heart palpitations and pale skin, it could be a sign of something more serious, and you should seek medical attention immediately.


While IBS used to be a diagnosis of exclusion, there are now at-home blood tests that can diagnose IBS-D or IBS-M that a gastrointestinal infection has caused. Since we now know how to test for IBS at home, we may start to see quicker diagnoses and better access to treatment.

How a Dietitian Can Help

A registered dietitian nutritionist can be an important part of your IBS care team.

Consider booking a virtual appointment with a registered dietitian at Nourish. They can help you manage your symptoms while still enjoying the foods you love.


Frequently Asked Questions

How can I confirm that I have IBS?

To confirm that you have IBS, you will need to undergo medical evaluation by an experienced doctor such as a gastroenterologist. They will review your symptoms, medical history, and family history. They may also order other tests such as blood tests, stool tests, and endoscopies to rule out other causes of your symptoms.

Recently, at-home IBS tests have become available. These tests measure specific antibodies that appear when IBS is caused by a gastrointestinal infection. These tests can only be used to diagnose IBS-D or IBS-M that is caused by an infection.

What are the symptoms of IBS?

The most common symptoms of IBS are abdominal pain related to your bowel movements and changes in your bowel movements, such as constipation or diarrhea. Other common symptoms of IBS include bloating, feeling like you haven’t completed a bowel movement, and whitish mucus in your stool.

Does IBS show up in a blood test?

IBS-D or IBS-M that is caused by a gastrointestinal infection will show up on the IBSchek or IBS-Smart at-home IBS tests. These tests measure the amount of two antibodies – anti-CdtB and anti-vinculin – in your blood. These antibodies are known to be elevated in people whose IBS-D or IBS-M was caused by an infection. These tests are not able to diagnose IBS-C, IBS-U or IBS that was not caused by an infection. 


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