Immunoglobulin E (IgE), serum

Alternate test name

IgE

Lab area

Clinical Biochemistry - General

Method and equipment

Equipment : Roche Cobas Pro e801

Method : Sandwich principle. Total duration of assay: 18 minutes.
▪ 1st incubation: IgE in the sample (6 µL), a biotinylated monoclonal IgEspecific antibody, and a monoclonal IgE-specific antibody labeled with a ruthenium complexa) form a sandwich complex.
▪ 2nd incubation: After addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin.
▪ The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier.
▪ Results are determined via a calibration curve which is instrument specifically generated by 2‑point calibration and a master curve provided via the cobas link.

Expected turn-around time

STAT/ Urgent: 4 Hours Routine: 24 Hours

Shipping information

Background and clinical significance

Immunoglobulin E (IgE) plays an important role in immunological protection against parasitic infections and in allergy (type 1 hypersensitivity). Type 1 hypersensitivity is characterized by the occurrence of allergic reactions immediately following re-exposure to an allergy-initiating antigen (allergen)
such as encountered in atopic disorders (e.g., allergic asthma), insect venom or latex and in some food allergies. The binding of the allergen to sensitized tissue mast cells or blood basophilic cells leads to cross-linking of the IgE on the cell membrane. This in turn causes cell degranulation and the release of inflammation mediators (e.g. histamine, serotonin, lipid mediators, proteases and cytokines), which produce the typical symptoms of type 1 hypersensitivity, an exaggerated immune response to foreign antigens, such as pollen, dust mites, and certain foods.

The IgE concentration in serum is normally very low as IgE is the least abundant antibody in serum (0.05 % of the IgG concentration). The IgE concentration is age-dependent, with the lowest values being measured at birth. Its concentration gradually increases and becomes stabilized between the age of 5‑7, although the IgE values vary greatly within particular age groups.

Elevated IgE concentrations can be found in patients with allergic diseases such as hay fever, atopic bronchitis and dermatitis.4 Normal IgE values do not, however, mean that an allergic disease can be ruled out. For this reason the quantitative determination of serum IgE concentrations is useful for clinical differentiation between atopic (i.e., predisposition to excessive IgE reaction) and non-atopic (non-IgE mediated) allergic diseases only in combination with other clinical findings.

Elevated serum IgE concentrations can also occur in non-allergic diseases, e.g. congenital immunodeficiency syndromes, HIV infection, graft-versus host disease, severe burns and parasitic diseases.