For in-vitro diagnostic use. The RIDASCREEN® Spec. IgE is an enzyme immunoassay (EIA) for the quantitative determination of specific IgE antibodies in human serum. When there is a suspected allergy according to the case history and in-vivo diagnostics, the test should be used for confirmation purposes. When the results of the in-vivo diagnostics are not in agreement with the case history, the test can also be used to determine specific IgE antibodies against allergens for the purpose of clarification.
The purpose of the immune system is to defend the body against pathogenic bacteria, viruses and other microorganisms. The defence reaction serves to protect the organism on initial contact with the pathogens and immunise it on repeated contact. All type I allergic reactions are preceded by an initial contact phase without symptoms during which class E specific antibodies (IgE antibodies) are formed. On repeated contact with the allergens which trigger the reaction, these IgE antibodies react with the allergens and lead to the release of mediators (usually from mast cells or mastocytes) such as histamine, leucotrien and prostaglandine etc. which lead to the symptoms of the allergy.
When there is an allergic reaction, the allergens causing the reaction can be identified by determining the specific IgE antibodies in the serum. This method can also be used to determine sensitisations without symptoms. The test is a cellulose-disc-based enzyme allergo-sorbent test (EAST). All reagents (A0041 or A0040) listed under section 4 are validated using the allergen discs (A0049) from R-Biopharm. When using these reagents with discs from other suppliers, it is the duty of the user to carry out a validation test.
The allergens are attached to the cellulose discs. In order to carry out the test, the allergen discs are placed in the wells of a microwell plate or are pre-coated according to the requirements of the doctor. Patient sera, standard sera and negative and positive controls are pipetted onto the allergen discs and incubated at 37 °C. During the incubation, the allergy-specific IgE antibodies attach themselves to the allergen. Material which does not attach is removed by washing. After this, an anti-human IgE antibody, which is conjugated with alkaline phosphatase, is also added. Any conjugate which is not attached is removed by washing. Substrate is then added and is dephosphorylated by the conjugated enzyme into a yellow product. The intensity of the yellow colour is proportional to the quantity of allergen-specific antibodies in the serum. A photometric measurement is carried out at 405 nm using a reference wavelength of 620 nm. Some allergens are attached to the cellulose disc via HSA (human serum albumin). In this case, an additional HSA disc must be used to determine the non-specific attachment of the allergen. The affected allergens are labelled on the R-Biopharm AG code lists by the suffix -HSA.
|Test format||Allergy Basic: single allergen discs (24 time the same allergen, delivered in 3 breakable strips of 8 cavities) , |
Allergy Advance: Microwell frame with 12 strips of 8 cavities each containing a panel of 8 different allergens
Allergy Active: Microwell plate with at least 42 allergens already inserted by R-Biopharm according to the customers record including reagents (valid only for Europe)
|Standard range||0.35 - 100.00 IU IgE/ml|
|Incubation time||135 min|
|Cut-off||The standard curve for RIDASCREEN® Spec. IgE is calibrated against the international reference preparation “2nd WHO IRP 75/502 for human IgE”.|
|Sensitivity||The analytical sensitivity of the test kit in relation to the determination of the standard material calibrated according to the WHO standard is less than 0.24 IU/ml. |
The diagnostic sensitivity is less than 0.35 IU/ml.
|Specificity||A selection of representative allergens from 11 Allergen groups was tested on various sera in comparison to the systems from another supplier of systems for allergy in-vitro diagnostics. This yielded a specificity of 91,2 %.|