BACKROUND

The worldwide frequency of allergies has increased significantly over the past decades. The term allergy is often used for Type I hypersensitivity reactions (immediate type reactions), whose symptoms generally occur within 30-60 minutes after contact with the allergen. The most frequent symptoms are: hay fever (rhinitis), conjunctivitis, hives (urticaria), allergic asthma and as the most dangerous manifestation anaphylaxis (the anaphylactic shock).

The allergens causing Type I hypersensitivity reactions are mostly proteins derived from the natural environment e.g. plant pollen, animal hair, food, mites, and insect venoms. The characteristics of Type I allergies is the involvement of allergen specific immunoglobulins (antibodies) of class E (sIgE). Hence, the detection of sIgE is an important tool of modern allergy diagnostics. The specific IgE EAST contributes to the diagnosis of Typ I allergies. It is available with 4 or 6 calibrators.

PRINCIPLE 

The Specific IgE EAST for the quantitative measurement of specific IgE is carried out in mircotiterplates. During the first incubation step patient specimens are incubated on allergen coupled discs. Surplus serum components are removed from the well by washing whereas allergen specific IgE remains bound. Subsequently, alkaline phosphatase (AP)-labelled antibody is added forming allergen/sIgE/anti-IgE conjugate complexes. The wells are washed again and the substrate solution p-nitrophenyl-phosphat (pNPP) is added and incubated, resulting in the development of a yellow color if conjugate is present. After stopping the enzymatic reaction with Sodium hydroxide (NaOH) the optical density (OD) of the colored reaction product is measured spectrophotometrically at 405 nm (reference wave length 620 nm). The sIgE concentration of the patient sample is proportional to the OD. Calibrators with defined concentrations of IgE (calibrated against WHO) are assayed simultaneously with the patient samples to generate a calibration curve. Unknown IgE concentrations of the test samples are calculated from this curve. (Download IFUs: 0540200PKL/0541000PKL & 0560200PKL/0561000PKL)

TOTAL IgE

Mostly, the occurrence of allergen specific IgE is accompanied by increased titers of total IgE in the blood of the patients. In these cases the titer can increase up to 1000fold. Usually, IgE concentrations are determined in international units per milliliter (IU/mL) wherein 1 IU corresponds to 2.4 ng of IgE. Highest IgE concentrations occur in patients with atopic dermatitis in which they often reach levels of 50.000 IU/mL. Moreover, increased titers of IgE can be observed in patients with parasitic diseases. Abnormal titers have also been described in certain autoimmune disorders. For the determination of total IgE the Total IgE-HRP EIA (08102CP, Enzyme Immuno Assay for the quantitative determination of Total IgE in human Serum or Plasma) is available. (IFU: 08102CP)

SYSTEMS

For the performance of specific IgE and Total IgE as well as ECP our ALLERG-O-SYSTEM is available, a system for the manual performance of tests. (Download: Flyer ALLERG-O SYSTEM)