Frequently Asked Blood Test Questions & Answers

Irritable bowel syndrome (IBS) is a chronic bowel problem that is associated with bloating, intermittent abdominal discomfort, and changes in bowel frequency and form. Diarrhea and constipation are common symptoms associated with IBS. Until now, the diagnosis of IBS has typically been a diagnosis of exclusion (meaning a diagnosis arrived at by excluding other conditions) because IBS symptoms are similar to those seen for celiac disease, Crohn’s disease, ulcerative colitis, and other chronic bowel diseases.
IBSchek is a simple ELISA*-based blood test that is highly predictive of an IBS diagnosis based on the presence of two antibodies—anti-CdtB and anti-vinculin. In a study of more than 2,500 patients conducted in 180 centers around the U.S., IBSchek was found to be more commonly positive in IBS with diarrhea (IBS-D) or IBS with mixed symptoms (IBS-M) compared to patients with Crohn’s disease, ulcerative colitis, and celiac disease. IBSchek is the first clinically validated blood test to confirm a diagnosis of either IBS-D or IBS-M. *ELISA = enzyme-linked immunosorbent assay.
IBSchek was developed based on the scientific discovery that irritable bowel syndrome often results from a previous episode of gastroenteritis. IBSchek tests for the presence of antibodies in the blood that were created by alterations in the intestinal microbiota resulting from acute gastroenteritis. It detects levels of an antibody to a toxin called CdtB (cytolethal distending toxin B), as well as vinculin, a human protein commonly found in nerves and the lining of the gut. While the test is more specific for anti-CdtB, the anti-vinculin component suggests that irritable bowel syndrome may be an autoimmune disease. The two levels enable a differential diagnosis of IBS from inflammatory bowel disease (IBD). The test only requires 3mL of patient's blood which can be drawn in a healthcare provider's office. For more information on the phlebotomy process refer to the IBSchek Phlebotomy Process.
IBSchek has been validated in diagnosing irritable bowel syndrome associated with diarrhea and mixed symptoms. Published studies have determined the cost savings—both direct and indirect—to the patient and healthcare system from receiving a faster diagnosis.
It's a simple process. A healthcare provider completes an IBSchek requisition form and submits it to CDI. HCP then completes the patient's blood draw and returns the specimen according to the instructions provided in the return shipping materials. Results are reported back to the healthcare provider within 24 hours of specimen receipt. For additional details, please refer to the IBSchek Phlebotomy Process overview. In the event the healthcare provider is unable to do the blood draw, you can contact CDI to arrange an alternative method by either visiting a partnering lab or using a mobile phlebotomy service that will draw the blood in the comfort of the patient's home. Contact CDI customer service for more details on these options - or (888) 258-5966.
This is a very important question. All tests are based on statistics. If the result is positive, it means there is a high degree of medical certainty that there is IBS-D or IBS-M, based on elevated levels of antibodies to Cdtb and/or vinculin. Having a high degree of certainty in irritable bowel syndrome diagnosis can reduce the cost to patients, providers, and the healthcare system as a whole, and can prevent treatment delays. IBSchek may prevent patients from having to undergo more invasive and costly exploratory tests, and, more precisely, it can direct next steps in patient treatment.
Although IBSchek is highly predictive of an IBS-D or IBS-M diagnosis, some patients will still have an inconclusive test result even though they suspect they have IBS. IBSchek tests for a specific mechanism known to cause irritable bowel syndrome. If the result is positive, you know the pathophysiological reason for your patient’s IBS and can determine the optimal approach to treat. However, an inconclusive IBSchek result is simply an indication that additional testing may be required to determine the underlying cause of your patient’s symptoms. One option that may be a viable consideration is the hydrogen and methane breath test for small intestinal bacterial overgrowth (SIBO). The SIBO breath test can identify an over-colonization of bacteria in the small intestine that may be directly contributing to a patient’s symptoms. This allows an accurate, quick diagnosis of common sources of digestive distress. Hydrogen and methane breath tests offer not only a patient-friendly alternative to more invasive diagnostic methods, but once the SIBO is identified, an appropriate antibiotic regimen or other appropriate treatment may be prescribed.
When the blood specimen arrives at a CDI-affiliated laboratory, the blood will be analyzed within 24 hours of receipt of the specimen. You can receive the results via our secured reporting system. *Please contact us at for sample report information.
Yes, some medications can affect the results of an antibody test. It is important to note that if you are taking steroids, anti-inflammatory medications, biologic agents, or any other immunosuppressive medications, you may not get a true reading, because these medications may change the level of antibodies in the blood. If a patient with suspected IBS has an inconclusive test and is taking any of these medications, repeat testing could be considered at a time when you are no longer taking these medications.
A positive IBSchek can confirm that you have IBS-S or IBS-M and that your disease is an organic condition based on the presence of validated biomarkers. IBSchek does not offer insight into which treatment is best for your irritable bowel syndrome patient. Confidently knowing you have IBS based on the presence of biomarkers, however, allows you to immediately initiate therapy without additional invasive and costly testing. You may want to consider a hydrogen and methane breath test for small intestinal bacterial overgrowth (SIBO) to help determine the type of antibiotic therapy to use. Treatment of a patient with methane-positive breath results differs from that of a patient with hydrogen-positive results. Once the SIBO is identified, an appropriate antibiotic regimen can be prescribed for the treatment of irritable bowel syndrome. Alternatively, some healthcare providers treat SIBO using other therapies and dietary modalities, including but not limited to the FODMAP diet.
It is now known, based on extensive human and animal research, that acute gastroenteritis leads to IBS. In animal studies, infection with campylobacter jejuni (C. jejuni) caused small intestinal bacterial overgrowth. C. jejuni infection also leads to the production of the anti-CdtB and anti-vinculin antibodies detected by IBSchek. In the same animal studies, antibody levels were related to the number of infections the animals experienced. However, irrespective of the number of infections with C. jejuni, bacterial overgrowth was more closely related to the antibodies than the number of infections.
Any healthcare provider who has applicable prescribing rights in his or her state or country of residence can order IBSchek. Patients may also order the test where Direct Access Testing is available and permitted.