When a person is allergic to a certain food they may have symptoms like nausea, vomiting, diarrhea, swelling of the lips, mouth, or tongue, in addition to others. It is important to find out if this is an allergic reaction so the food can be avoided.
The RAST blood test may be ordered if the doctor thinks you have food allergies. This test measures the amount of allergen-specific lgE in the blood to detect an allergy to a particular substance. Each allergen-specific lgE antibody test is separate and very specific–such as testing the egg whites and then testing the egg yolks. If allergen-specific antibodies are found, there may be an allergy to a certain food. Having lgE antibodies may only mean you are sensitized to the allergen. You were exposed, but you may not be allergic.
The RAST test should be compared to your history of allergies. Your doctor will meet with you after the results come back to discuss the findings. If it is found that you have a food allergy, you may need to make changes to your diet.