Use of the LEAP Mediator Release Test to Identify Non-IgE Mediated Immunologic Food Reactions that Trigger Diarrhea Predominant IBS Symptoms Results in Marked Improvement of Symptoms Through Use of an Elimination Diet

American College of Gastroenterology, Annual Scientific & Educational Meeting, Orlando, Florida, November 2004, Fred H. Williams, MD, Department of Gastroenterology, St. John’s Mercy Medical Center, St. Louis, Missouri, United States


Diarrhoea predominant IBS (D-IBS) is a common condition that is often refractory to standard therapy. Though some treatments may improve certain symptoms, there is no treatment that has been shown to result in the improvement of global D-IBS symptoms. The Lifestyle Eating and Performance Mediator Release Test (LEAP MRT) is an in vitro test that detects non-IgE mediated food reactions that can trigger D-IBS symptoms. We report on our early experience with this dietary modification program.


Ten patients who met Rome II criteria for D-IBS are reported in this study. These patients presented to our community-based gastroenterology practice and were evaluated by a gastroenterologist. Evaluation for other causes of their symptoms was based on the patient’s previous evaluation and the discretion of the gastroenterologist. Typically, if not already employed in the past, a trial of standard therapy such as fibre and anti-spasmodic agents was attempted. If the patient didn’t improve, they were then offered LEAP MRT testing. Using an in vitro assay, the patient’s blood was tested for non-IgE mediated reactivity to150 foods and food additives. A specific elimination diet that omitted the reactive foods was then designed for the patient. A Symptom Survey was employed to follow the patients for improvement in D-IBS as well as systemic symptoms. The survey graded multiple GI and systemic symptoms on a scale of 0-4 with increasing severity represented by a higher number. The maximum points possible for the entire survey was 236 and for the GI portion was 36.


Prior to beginning the LEAP MRT based elimination diet, the average score for the entire survey was 56.9 and for the GI portion was 19.1. After at least one month on the diet, the average scores had decreased to 26.3 and 6.3 respectively. Patients generally reported a marked improvement in their D-IBS symptoms, decreased systemic symptoms, and an overall increase in their feeling of well-being.


The LEAP MRT identifies non-IgE mediated immunologic food reactions that trigger D-IBS symptoms. Elimination of these foods from the diet results in a marked improvement in D-IBS and other systemic symptoms.