This test is used to confirm the specific allergen that has affected a person. Hence, this test is ordered only after previous evaluation and proper assessment of the medical history of the patient. A positive result may indicate that allergic signs and symptoms are caused by exposure to the allergen. Clinical manifestations of immediate hypersensitivity (allergic) diseases are caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE antibodies interact with allergen.