IgE stands for immunoglobulin E, one of the classes of immunoglobulins (also called antibodies) that are in the blood. The protective role of IgE is not clear.
The 'low', 'normal' and 'high' ranges vary with age, and are also lab-specific. However, a reasonable normal range is 0.002-0.2mg/dl.
Low levels of IgE can occur in a rare inherited disease that affects muscle coordination (ataxia-telangiectasia). It is frequently increased in parasitic infestations and atopic individuals.
A high level of IgE can indicate a parasite infection. Also, high levels of IgE are found in people who have allergic reactions, asthma, atopic dermatitis, some types of cancer, and certain autoimmune diseases. Rarely, a high level of IgE may indicate IgE multiple myeloma.
IgE myeloma is extremely rare and should be sought after abnormal protein electrophoresis (restriction) and/or abnormal kappa/lambda ratio unexplained by IgG, IgA, or IgM. The principal limitation of this test is the wide overlapping range of IgE values between atopic and non-atopic disease states. IgE is elevated 4-30 times normal in various diseases, among which atopic disorders and parasitic disorders are most prominent.