CD63 and Allergy: After multivariable analyses, only the basophil activation markers were retained for severity and threshold, meaning that the BAT alone was more discriminative in predicting the severity (CD63 peanut/anti-IgE, P = .001) and threshold (CD-sens, P = .020) of allergic reactions to peanut than the other allergy tests or the combination of the BAT with the other allergy tests (Table III).