Allergy blood testing is the same as any other blood test: a small amount of your blood is sent to a lab for analysis.
Allergy blood tests can detect Immunoglobulin E (IgE) in your blood. IgE is an antibody produced by the immune system in connection with a reaction to protect us from outside intruders such as parasites.
When you’re allergic to, for example pollen, certain foods or insect stings your immune system overreacts to the otherwise harmless substance and triggers the same defence mechanisms as against parasitic infections. The body produces IgE antibodies specific to the allergen it’s trying to fight. These antibodies tell cells in your body to release certain chemicals. And it is those chemicals that cause allergy symptoms.
Allergy blood tests identify and measure specific IgE antibodies in your blood. Since IgE antibodies are different depending on what they are reacting to, allergy blood testing can point to what allergens your body is reacting to.