Skin testing for allergies is done on the patient's forearms or back during the initial evaluation visit. Using a multitest applicator, allergy extracts for more than 40 allergies are placed on the arms or back. If the patient is allergic, reactions in the form of hives begin immediately. After 20 minutes, the size of all the reactions are measured and recorded. The results are evaluated by the allergist to determine which allergens the patient is allergic to and prescribe the most effective procedure kit.