Main Page | See live article | Alphabetical index A RAST test (short for radioallergosorbent test) is a blood test used to determine what a person is allergic to. This is different from a skin allergy test, which determines allergy by the reaction of a person's skin to different substances. A RAST test detects the amount of IgE in someone's blood that reacts specifically with certain allergens. IgE is the antibody associated with the allergic response: if a person had a high level of IgE directed against pollen, the test would indicate that person is allergic to pollen. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.