What are the normal levels of IgE?

A normal IgE level ranges from 0 to 380 international units per milliliter, according to the Marshall University School of Medicine. IgE is an antibody that binds to allergens and triggers an inflammatory response.

IgE antibodies trigger an inflammatory response by binding to mast cells, states the Asthma and Allergy Foundation of America. Someone with an increased number of IgE antibodies is likely to have at least one allergy, reports the American Association for Clinical Chemistry. The total IgE test indicates an allergic response, but it does not identify the substance responsible for triggering the allergy. To identify a specific allergy, the allergen-specific IgE test is used. In some cases, elevated IgE levels are caused by parasitic infections.