Allergy testing, also known as “skin, prick or blood testing”, is a method for determining to what substances a person is allergic. Skin allergy testing is the most common, reliable and relatively painless form of allergy testing. Skin tests are done by placing little drops of each suspected allergen on your forearm then lightly pricking the skin with a plastic applicator to break the top layer; also sometimes small needles actually inject the allergen directly under the skin. A timer is set for 10 minutes and if the skin is itchy, red or has welts it is scored on a 0-4 scale to determine which allergen you are allergic to.
Blood tests are generally used when skin tests might be unsafe or won’t work, such as if you are taking certain medications or have a skin condition that may interfere with skin testing. There are methods of allergy testing that the American Academy of Allergy, Asthma & Immunology (AAAAI) believes are not useful or effective. These tests are performed by non-allergy practitioners or people who call themselves healthcare professionals but lack formal training and national board-certification in the field of allergy and immunology