Skin Prick test
During a skin prick allergy test an "allergist places a drop of solution containing the food allergen on your forearm or back. Using a small plastic probe or needle, the doctor gently pricks or scratches the skin to allow a tiny amount of the solution to enter just below the surface." (FARE). After a certain amount of time - 15 minutes is the standard - the doctor will come back and check if there is any reaction to the skin (Gupta). "Positive results are indicated by a wheal – a raised white bump surrounded by a small circle of itchy red skin." (FARE). Having a large reaction to an allergen means you have that allergy having little to no reaction means you do not. The larger the reaction the more allergic you are to that allergen. Besides allergens that are pricked onto the body the allergist will also prick saline and histamines into your skin. These two solutions are called controls. The saline you should not react to and the histamine you should react to (Gupta). These two solutions help determine how your skin reacts and helps allergest determine what you are allergic to. |
Blood test
An allergy blood test puts your blood though a computer system to detect allergens (Gupta). The tests "detect and measure the amount of allergen-specific antibodies in your blood" (Miller). These allergen specific antibodies make your cells release certain chemicals called Immunoglobulin E (IgE) which is an antibody linked to the body's allergy reaction (Miller). In easier terms a blood test looks for the allergens in antibody form when there is a certain amount of IgE of an allergen you have that allergy. Blood allergy tests are the most basic allergy test you can get and are usually done by doctors not allergist. |
Food/Oral challenge
A food challenge is primarily used for those who have an existing allergy to confirm that they have that allergy or to see if they have out grown the allergy. During a food challenge "You eat the food or take the capsule under strict supervision. After eating the food or taking the capsule, you will be monitored to see if a reaction occurs." (Cleveland Clinic). After your first dose if you have no reaction you will be given lager doses of that food or capsule until you have a reaction or pass the test (Gupta). Food challenges can be done in two ways. One where both the patient and doctor know what is being eaten or through a double-blind placebo controlled test. In this instance the allergest and the patient do not know if they are eating the allergen. In this test same thing happens except you do not know if you are eating the allergen or not. "Food challenges are the only way to confirm or deny if someone is allergic to a food or not" (Cleveland Clinic). |