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There are options when it comes to testing to identify allergic triggers. Discover the differences on each kind of test and talk to your healthcare professional about which combination may be right for you.
A blood test is a quick and simple test. It measures the amount of antibodies in the blood (IgE), which is an indicator of allergic sensitization. This powerful diagnostic tool can test for hundreds of allergens, such as pollen, mold, food, and animal dander and can be performed at any age. A blood test can help your healthcare professional determine if you are allergic and to what. A small sample of blood is drawn and sent to a laboratory for analysis. The results are returned a few days later for your healthcare professional to interpret.
There are two options for blood testing in your allergy management plan. Whole allergen testing can identify allergic triggers and can help your healthcare professional rule allergy in or out.2-4 Allergen component testing can pinpoint the allergenic proteins that may be causing your allergy symptoms.5 While the first step can help your healthcare professional determine if you are allergic to peanuts, a second step may be necessary to determine exactly which protein triggers your reaction. And knowing which protein you’re allergic to is important for your healthcare professional to determine if your reactions more likely to be severe and systemic, or mild and localized and if you’re at risk for cross-reactivity reactions.
THE BENEFITS OF A BLOOD TEST
Also called a specific IgE (sIgE) blood test—this powerful tool can aid in accurately diagnosing your allergies. There are fewer limitations on who can receive this type of test or when it can be performed. A blood test may also help your healthcare professional discover hidden risks, like allergic reactions caused by cross-reactivity.
A skin prick test involves puncturing or scratching the upper layer of your skin, to introduce a very small amount of a suspected allergen to your immune system. If you are allergic, a reaction similar to a mosquito bite may appear, usually within 20 minutes.
Although SPT can be done at a young age, the repeated scratching or pricking can be traumatic for small children. And if you have darker skin, it may be hard to read the results. SPT can be difficult to use in the presence of a condition like eczema, or if you are actively taking an antihistamine. And the test needs to be performed at facilities where they are equipped to deal with the possibility of an anaphylactic reaction. 6
A challenge test, in connection with a blood test or SPT, is a powerful diagnostic tool. Also called an Oral Food Challenge (OFC), it is used to establish a correct diagnosis, which can be guided by the results from a blood test. When administered, a person is fed a small, but increasing portion, of a food that they have a suspected allergy to. They are monitored closely for any reaction; therefore, an OFC is usually performed in a hospital setting. If there is no reaction, they are fed of a larger portion of the food, up to a serving size. But, if a reaction occurs, the test stops.
A challenge test can be used to confirm a food allergy or to see if you have outgrown a food allergy. Challenge tests should not be performed on someone with a history of a recent anaphylactic reaction.
A provocation test is very similar to a challenge test. The main difference is that a provocation test can be performed in the nose, eyes or lungs, as well as the mouth. In a provocation test, a person is given small, but increasing quantity, of their suspected allergen and monitored closely for any reaction. If there is no reaction, they are given more until a response is seen. But, if a reaction occurs, the test stops. This test is rarely performed, and usually in a hospital setting.