ImmunoCAP™ Drug Allergens

Quantify specific IgE antibodies with ImmunoCAP™ Drug Allergen Components, essential tools to aid in the diagnosis of allergic conditions. IgE antibodies appear in human serum and plasma as a result of sensitization to a specific allergen. Measurement of circulating IgE antibodies provides an objective assessment of sensitization to an allergen. In general, low IgE antibody levels indicate a low probability of allergic disease, whereas high antibody levels to an allergen show a higher correlation with an allergic disease.

ImmunoCAP Specific IgE offers the laboratory:

• Truly quantitative measuring range from 0.1 to 100 kUA/L
• Intra-assay CV (%) comparable to routine clinical chemistry immunoassays
• Excellent consistency over time, and between countries, systems, labs and persons

Expected test values
ImmunoCAP Specific IgE detects IgE antibodies in the range 0.1 to 100 kUA /l, where A represents allergen-specific antibodies. The result is reported quantitatively. In clinical practice, 0.35 kUA /l has commonly been used as a cut-off. A large number of studies have been performed to evaluate the clinical performance of ImmunoCAP Specific IgE tests in allergy diagnosis. Clinical performance is expressed as sensitivity, ranging from 84 to 95%, and specificity, ranging from 85 to 94%. Sensitivity and specificity were reported from multi-center studies including several hundred patients tested for a range of different allergens.

• Specimen collection and preparation
• Use serum and plasma (EDTA or heparin) samples from venous or capillary blood
• Collect blood samples using standard procedures
• Keep specimens at room temperature (RT) for shipping purposes only
• Store at 2–8°C up to one week, otherwise store at –20°C
• Avoid repeated freezing and thawing

Note: Blood samples for testing ImmunoCAP drugs and venom should be collected during or close to the event, preferably not later than 6 months after exposure. If the test result is negative and an IgE-mediated reaction is still strongly suspected, it is advisable to draw a new sample and repeat the test at 5 to 6 weeks.

The presence of specific IgE antibodies is useful to identify the allergens that elicit symptoms and signs of allergy in patients with respiratory allergic diseases including asthma, food allergy, and anaphylactic sensitivity.

Knowing IgE antibody levels provides guidance to clinicians to:

• Identify offending allergens
• Tailor advice to individual patients
• Indicate development of tolerance (food allergy, specific immunotherapy)
• Inform optimized individual medical treatment plans
• Refer to specialists appropriately
• Evaluate whether or not specific immunotherapy is an option

Specific IgE testing also aids in the identification of patients at risk of:

• The allergy march – a progression of skin symptoms to respiratory symptoms
• Severe symptoms including asthma exacerbations – a progression of mild symptoms to severe symptoms
• Progression of recurrent symptoms to persistent symptoms

As in all diagnostic testing, a definitive clinical diagnosis should be made by the clinician after evaluation of all clinical and laboratory findings.