Allergy is conditions when a hypersensitivity reaction happens with a certain element, called as an allergen, which is commonly not reactive to ordinary individuals. Allergic diseases involve various organs or systems in the body. The purpose of allergy tests is to make a diagnosis of allergic diseases and to identify the affecting allergens. In vivo tests, more relevant in clinical situation, include skin test, patch test and provocation test. In in vitro tests, there are specific IgE test, histamine releasing assay, and lymphocyte activation test, safer and more objective than in vivo tests. In the view point of clinical practice, skin test, provocation test, total IgE test and specific IgE test were reviewed in depth.