Basophil Activation Test (BAT)
The Basophil Activation Test (BAT) resembles an allergic reaction in a vial. The test is based on a drawing a simple venous blood sample from an individual. The Basophils are the allergic cells present in such a sample. By adding the suspected allergenic substance, like PEG, to a small amount of blood in a test tube, basophils can be specifically activated. This BAT is a reliable biomarker for potential in vivo hypersensitivity reactions to the tested substance. The basophil activation results in the degranulation and release of pro-inflammatory mediators as well as the expression of activation markers. The BAT test detects the expression of such markers like CD63 by a flow cytometry technique.