Whats the difference between blood tests and skin tests?
Testing for traditional IgE mediated food allergies can be done with either blood testing (often called RAST or ImmunoCAP testing) or skin testing. Both can be helpful and both have advantages and disadvantages. RAST (blood) tests measure the amount of allergic antibodies a person has to a particular food. They can be used to confirm an allergy if there is already a history of a reaction. A positive RAST test without a history of a reaction does not mean you have a food allergy. It’s also important to know that a high RAST test result does not necessarily mean your food allergy is severe. Some individuals have very high RAST levels but relatively mild reactions, while other individuals have anaphylaxis with low RAST levels. Skin tests can also confirm an allergy but their advantage is that they’re more accurate at predicting whether you’ve outgrown your food allergy or not.
