| Web: | mayocliniclabs.com |
|---|---|
| Email: | mcl@mayo.edu |
| Telephone: | 800-533-1710 |
| International: | +1 855-379-3115 |
| Values are valid only on day of printing | |
| Web: | mayocliniclabs.com |
|---|---|
| Email: | mcl@mayo.edu |
| Telephone: | 800-533-1710 |
| International: | +1 855-379-3115 |
| Values are valid only on day of printing | |
Innovative bile acid malabsorption panel transforms gastrointestinal care
Eye on Innovation
Mayo Clinic Laboratories has introduced a pioneering diagnostic test for bile acid malabsorption, a condition significantly contributing to chronic diarrhea. In an interview, Michael Camilleri, M.D., D.Sc., from the Division of Gastroenterology and Hepatology at Mayo Clinic, and Leslie Donato, Ph.D., from the Department of Laboratory Medicine and Pathology at Mayo Clinic, shared insights into this innovative test, detailing its development and transformative potential for patient care.
Mayo Clinic’s journey with bile acid diarrhea began in the 1970s with Dr. Alan Hoffman’s landmark study in the New England Journal of Medicine, which established the link between bile acid malabsorption and diarrhea. However, the internationally recognized 75SeHCAT test was never approved in the United States. Seeing an urgent need for a reliable diagnostic method, Dr. Camilleri and his team embarked on a mission to fill this gap about 15 years ago.
“We started noticing an increasing number of patients with chronic diarrhea who hadn't undergone the usual surgeries that cause bile acid malabsorption,” Dr. Camilleri explained. “Studies from many different countries were showing that 25 to 50 percent of these patients had bile acid diarrhea based on various tests, including the gold standard test.”
This discovery led to the creation of the 48-hour fecal bile acid excretion test, which was paired with the 48-hour fecal fat test for a comprehensive diagnostic approach.
Dr. Donato added, “Dr. Camilleri identified patients with irritable bowel syndrome with diarrhea (IBS-D) who had bile acid malabsorption. This led to our research efforts to develop better diagnostic methods. Patients with this condition have too much bile acid in the colon, causing watery stool and diarrhea.”
Despite its effectiveness, the complexity of the 48-hour stool test prompted a search for a simpler solution. “We developed a blood test called the serum 7α-hydroxy-4-cholesten-3-one (C4) test to measure bile acid synthesis in the liver,” Dr. Camilleri said. Although the test had high specificity, the sensitivity of the blood test alone was limited as it could only detect 25% to 30% of cases.
Combining the blood test with a single stool sample led to the creation of the bile acid malabsorption panel.
“This new panel simplifies the diagnostic process, eliminating the need for special diets or prolonged stool collection, making it much more convenient for both patients and clinicians,” said Dr. Camilleri.
The bile acid malabsorption panel has been in clinical use at Mayo Clinic for the past 18 to 24 months. “Our consultants are already utilizing this test for patients,” Dr. Camilleri confirmed. The test has applications in other gastrointestinal diseases like Crohn’s disease, microscopic colitis, and celiac disease, but it can also be applied to identify the cause of diarrhea in hematology and oncology conditions such as bone marrow transplants and graft-versus-host disease.
Dr. Donato highlighted the significance of this test, saying, “Bile acid malabsorption was previously an underrecognized cause of chronic diarrhea. Through our research, we've shown that it plays a major role, with a prevalence in the community that is comparable to celiac disease. This has enabled effective treatments that dramatically improve patients' quality of life.”
Developing this test was no small feat, requiring significant collaboration and funding from the National Institutes of Health (NIH). “The NIH support was essential for conducting prospective tests and establishing normal values,” Dr. Camilleri said. He emphasized the crucial contributions of Mayo Clinic’s Immunochemistry core lab and scientists like Dr. Ravinder Singh and Dr. Roy Dyer.
One of the major challenges was ensuring patient adherence to the 100-gram fat diet and correct stool sample collection. “Our research team played a vital role in educating and guiding participants,” Dr. Camilleri explained. Transitioning to a simpler method involving a fasting blood sample and a single stool sample has greatly simplified the process.
“I transitioned the test from a research setting to a clinical production laboratory,” said Dr. Donato. “This involved working closely with Dr. Camilleri and the Immunochemistry core lab staff to ensure the test was robust and ready for clinical use.”
Dr. Camilleri and his team continue to refine the test to improve diagnostic accuracy. “A group in Copenhagen suggested adding bowel movement consistency data to the blood and single stool biochemical measurements, but we haven't found it necessary,” he said. The test's effectiveness has been validated in several international centers in Denmark and England, reinforcing its reliability.
Dr. Donato added, “We've expanded the test's application to various GI conditions, not just IBS-D. This expansion is exciting as it opens new treatment avenues for patients with chronic diarrhea.”
Dr. Camilleri is optimistic about the future. “We are constantly exploring ways to enhance the diagnostic accuracy of our test,” he stated. The international validation underscores the test’s potential to become a global diagnostic standard.
Mayo Clinic Laboratories’ bile acid malabsorption panel marks a significant leap forward in diagnosing and managing chronic diarrhea. Its simplicity and high diagnostic accuracy promise to improve patient care and clinical outcomes, both within Mayo Clinic and around the world.
Reflecting on the journey, Dr. Camilleri said, “The success of this bile acid malabsorption test is a testament to the remarkable collaboration and dedication across our departments. Alongside dedicated scientists like Dr. Ravinder Singh and Dr. Roy Dyer, we transformed a research concept into a clinical reality. Our ability to innovate and bring this test to clinical practice is a direct result of the teamwork and expertise of our scientists and researchers. This breakthrough not only enhances our diagnostic capabilities but also significantly improves patient care.”
Dr. Donato echoed this sentiment by sharing, “It's incredibly satisfying when patients thank us for this testing. They've often struggled with chronic diarrhea for years without answers. Now, with our test and subsequent treatment, their symptoms are alleviated, dramatically improving their quality of life."
