People can use blood test kits at home to test for some types of IBS. The results can help doctors make a diagnosis, but other tests are also necessary.

Irritable bowel syndrome (IBS) is a common digestive disorder that affects the large intestine (colon). Around 12% of people in the United States have IBS.

Doctors diagnose IBS by thoroughly evaluating a person’s medical history, performing a physical examination, and ordering certain diagnostic tests.

The diagnostic process largely involves ruling out other conditions. However, there are at-home test kits for IBS that may help doctors with the diagnostic process.

This article examines IBS home test kits, how a doctor may diagnose IBS, current IBS treatment options, and more.

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Yes, it is possible to use IBS diagnostic and monitoring tools at home.

For example, a person’s doctor may have them complete the IBS Severity Scoring System (IBS-SSS) and the Irritable Bowel Syndrome Quality of Life (IBS-QOL) at home.

These are common questionnaires that help doctors monitor IBS symptoms over time and assess the impact of IBS on quality of life.

Additionally, people can use an at-home test kit with a doctor’s approval.

Read about 10 signs and symptoms of IBS.

IBSchek and IBS-Smart are two at-home blood tests that can help in the diagnostic process for IBS.

Both tests measure anti-CdtB and anti-vinculin. These are antibodies associated with IBS-D and IBS-M that can develop from gastrointestinal infections, such as food poisoning.

IBS-D is the diarrhea-predominant subtype of IBS, and IBS-M is a mixed subtype involving both constipation and diarrhea.

However, neither test can help diagnose IBS-C, the constipation-predominant subtype, because anti-CdtB and anti-vinculin levels are typically not elevated in those cases.

IBSchek, the first blood test for IBS, reports the results as “supportive” for IBS-D or IBS-M if either antibody is present at a level greater than the reference intervals. It reports the results as “not supportive” if both antibodies are less than the reference intervals.

IBSchek is more than 90% specific, meaning that negative results are accurate 90% of the time. It is also around 40% sensitive, meaning that positive results are accurate approximately 40% of the time.

Like IBSchek, IBS-Smart also measures anti-CdtB and anti-vinculin levels in the blood. However, IBS-Smart may provide more useful test results.

For example, the validation study for IBS-Smart shows that elevated levels of the antibodies may indicate IBS with up to 100% positive predictive value, depending on whether there is an elevation in one or both antibodies.

While IBSchek and IBS-Smart may help diagnose IBS in some people, there are a few points to remember:

  • These tests check for anti-CdtB and anti-vinculin, the antibodies associated with a previous gastrointestinal infection. However, not everyone with IBS has the condition due to a previous gastrointestinal infection.
  • IBSchek and IBS-Smart do not apply to IBS-C or IBS-U, which is the unclassified subtype of the condition.
  • A negative test result does not necessarily mean a person does not have IBS.
  • Some research highlights the need for further studies to determine whether anti-CdtB and anti-vinculin are potentially translatable to clinically useful diagnostic tests.

Only a licensed doctor can order IBSchek, but they can have it shipped directly to their patient.

Anyone can order IBS-Smart after completing a questionnaire about their symptoms. Once a licensed doctor reviews the questionnaire and determines the person is eligible, the company ships it to the person.

Both tests require a blood draw, typically at a doctor’s office or an independent blood draw lab, and come with prepaid packaging for the person to send back.

After analyzing the blood sample, the company sends the results to the person and their doctor, if applicable.

The diagnostic process may vary depending on the individual case and the doctor’s judgment.

Typically, a doctor performs a physical exam and asks about family and personal health history, including IBS-related symptoms.

Then, they use the Rome IV criteria to diagnose IBS.

The Rome IV diagnostic guidelines require a person to have recurrent abdominal pain at least 1 day per week, on average, for the past 3 months, associated with two or more of the following criteria:

  • related to defecation
  • change in stool frequency
  • change in stool appearance

The Rome IV criteria categorize IBS into the following subtypes depending on the predominant symptom:

  • IBS with predominant constipation (IBS-C)
  • IBS with predominant diarrhea (IBS-D)
  • IBS with mixed bowel habits (IBS-M)
  • IBS unclassified (IBS-U)

Additionally, a doctor may order diagnostic tests.

Currently, there are no specific tests to diagnose IBS definitively. Even IBSchek and IBS-Smart are unable to check for IBS-C and IBS-U.

However, certain tests can help doctors rule out other conditions that can mimic IBS. These tests include:

Read about treatment options for IBS.

IBSchek and IBS-Smart are two at-home test kits for IBS. While the tests are imperfect and can only identify IBS-D and IBS-M, they may help decrease the number of other tests a person typically undergoes during the IBS diagnostic process.