Can someone explain the rast test to me. i'm very confused on how it's supposed to inform you on an allergy. ?

Not very helpful: I'm not an allergist, but I think most of my allergist colleagues here will agree that the results of the RAST radioallergosorbent test are a small piece of the picture in allergy diagnosis. Many people have IgE antibodies against various things that don't make them sick. Trying to elimnate these will generally give you no benefit and be very inconvenient for you and those around you.

Immune response : when exposed to an allergen the body produces, amongst others, a specific protein called IgE. RAST is a test that can detect those specific IgE proteins. When the level is elevated, you are considered allergic to that particular allergen

Allergy testing: The "RAST" test is an older technology that is a blood allergy test. Most labs don't do this test anymore and instead use something called "immunocap" which is much more accurate. People still say "RAST" to mean blood testing for allergies. The test has similar results to skin prick testing and shows the level of allergy protein (IgE) against different allergens in your blood.

It's just a number: You are correct to be confused; some providers assume you can diagnose allergies by tests. RAST only shows that you have an allergic antibody (IgE) to a specific item. A positive test is necessary, but not sufficient (enough) to say you are allergic. Allergists are trained in interpreting blood and skin tests can help you understand what RAST test means for YOU.

RAST test: RAST, is less commonly used, as it involves radiation to detect allergic antibodies in the blood. A more common test is immunocap testing which does not use radiation to detect blood allergic antibodies. In some settings the test (aeroallergens, venoms), it is very accurate to predict reaction, however, in food testing, the history is required and food challenge is the gold standard to diagnose