Immunoglobulin E (IgE) is a type of antibody (or immunoglobulin (Ig)"isotype") that has only been found in mammals. IgE is synthesised by plasma cells. IgE's main function is immunity to parasites such as helminths like Schistosoma mansoni, Trichinella spiralis, and Fasciola hepatica. Total IgE is utilized during immune defense against certain protozoan parasites such as Plasmodium falciparum. Total IgE may have evolved as a last line of defense to protect against venoms.

Clinical Significance

Elevated concentrations of IgE are generally thought of in the context of allergic disease. However, increases in the amount of circulating total serum IgE can also be found in various other diseases, including primary immunodeficiencies, infections, inflammatory diseases, and malignancies. Total IgE measurements have limited utility for diagnostic evaluation of patients with suspected allergic disease, except for allergic bronchopulmonary aspergillosis (ABPA). An elevation of total IgE is part of the diagnostic criteria for ABPA, although the specific diagnostic concentration is dependent on certain patient characteristics.
For patients with an established diagnosis of allergic disease, measurement of total IgE is necessary for identification of candidates for omalizumab (anti-IgE) therapy and for determination of proper dosing.


Intent use

✔ Evaluation of patients with suspected diseases associated with elevations in total immunoglobulin E (IgE), including allergic disease, primary immunodeficiencies, infections, malignancies, or other inflammatory diseases.
✔ Diagnostic evaluation of patients with suspected allergic bronchopulmonary aspergillosis.
✔ Identification of candidates for omalizumab (anti-IgE) therapy.