Allergy is a hyper-sensitivity to a specific substance which, if inhaled, ingested, touched or injected, causes characteristic symptoms.
The Total IgE measures the overall quantity of immunoglobulin E in the blood. It can only be used to detect an allergic response in the body rather than detecting which allergen is someone allergic to. IgE Speficic tests are done to detects the speficic allergens that someone can be allergic to.