Researchers have developed a new type of blood test that can detect the existence of allergies and determine the patient's severity of reactions to an allergen.
The basophil activation test (BAT) is a new method that works by counting the number of the basophil immune cell activated in the blood after exposure to certain food. The Mount Sinai researchers from the Mindich Child Health and Development Institute and the Jaffe Food Allergy Institute believe their new method can potentially eliminate the need for skin prick tests used by physicians to measure the amount of a protein called allergen-specific lgE and the more dangerous tests, which cannot determine a patient's severity of reaction to certain foods.
The only way doctors can currently assess the severity of reactions is to have the patient go through a food challenge, or having the patient eat the food he is allergic to, under the watchful eye of his physician. The method is not without its flaws, chief of which is the danger patients are subjected to by having them eat food that can cause severe reactions.
"Although food challenges are widely practiced, they carry the risk of severe allergic reactions, and we believe BAT testing will provide accurate information in a safer manner," said researcher Ying Song, physician at the Mount Sinai Hospital. "While providing crucial information about their potential for a severe allergic reaction to a food, having blood drawn for BAT testing is a much more comfortable procedure than food challenges."
To assess the accuracy of the new blood test, the researchers recruited 67 subjects who were 12 to 45 years old and had them undergo food challenges involving peanut, tree nut, fish, shellfish, and sesame, which are some of the most common allergy-causing food, and placebo. Before the food challenge, they obtained blood samples from each individual to see if their basophil levels correlated with the severity of their allergic reactions as seen during the food challenge.
While the researchers believe BAT can eventually replace skin prick tests and food challenges, the method is for now restricted to the laboratory.
"Although the blood basophil activation test has been shown to be an important addition to the tools available for discriminating between allergic and non-allergic individuals and predicting the severity of food allergy reactions, at this time it is only approved for research purposes," said Xiu-Min Li, senior author of the study and professor of pediatrics at the Icahn School of Medicine.
The study is published in the Annals of Allergy, Asthma & Immunology.
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