BlueCross BlueShield of Tennessee Medical Policy Manual

In Vitro Particle Size Measurement for Screening Hypersensitivity Reactions to Foods and Chemicals


In vitro particle size measurement for screening hypersensitivity reactions involves the measurement of the aggregate release of inflammatory mediators from an individual's immunocytes after exposure to various food extracts and chemicals (e.g., food additives). A determination is made of the difference in volume of circulating immunocytes and plasma before and after an in vitro antigen challenge.

An example of this technology is the Mediator Release Test® or MRT®.  For this test, portions of an individual's blood sample are incubated with various food extracts and food additives (typically 150 different substances). The degree of reactivity is determined by the degree of mediator release from the cells. A response, change in cellular and plasma volume, is thought to indicate a hypersensitivity reaction and results are used as a basis for modifying an individual’s diet. The MRT® is one component of the Lifestyle Eating and Performance (LEAP®) Program of oligoantigenic dieting. This type of testing has been promoted for individuals with, among other conditions, irritable bowel syndrome, chronic fatigue syndrome, migraine headaches, and dermatologic conditions (e.g., eczema, dermatitis).




Well-designed studies in peer-reviewed journals are not available to determine the efficacy of this technology related to hypersensitivity reactions to foods (e.g., sensitivity to cow's milk) and chemicals.


American Academy of Allergy, Asthma & Immunology, American College of Allergy, Asthma & Immunology and the Joint Council of Allergy, Asthma & Immunology. (2014). Food allergy: a practice parameter update – 2014. Retrieved October 20, 2016 from

National Institute for Health and Care Excellence. (2011). Food allergy in under 19s: assessment and diagnosis. Retrieved October 20, 2016 from

National Institute of Allergy and Infectious Diseases. (2010). Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. Retrieved October 20, 2016 from




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