The gold standard to diagnose food allergy is an oral food challenge (OFC), but it can cause severe allergic reactions in some individuals. Reliable laboratory tests would eliminate undesirable aspects of OFCs, allowing easier and safer diagnoses and assessments of clinical responses to treatments. 

In a recent letter to the editor in The Journal of Allergy & Clinical Immunology (JACI), researchers, including Benaroya Research Institute and Immune Tolerance Network's Henry T. Bahnson, investigated whether LAD2 cells, a mast cell line, could be passively sensitized with patient plasma and used to monitor peanut allergy. This assay, referred to as the mast cell activation test (MAT), was able to diagnose peanut allergy, with an apparent ability to distinguish between peanut allergic and peanut sensitized, non-allergic individuals. 

Advantages of MAT are that it can be performed with banked frozen plasma. Additionally, patients with severe reactions following OFC had greater mast cell activation levels compared to patients with reactions that were not severe, indicating MAT may be able to identify patients at high risk for developing dangerous complications during OFC. For these reasons, MAT may be a very useful laboratory test for monitoring food allergies and the responses to allergen therapy over time.   

Additional information about this research is available at The Guardian and Helio.com.