Phadia ImmunoCAP

The Phadia ImmunoCAP and ISAC systems have the ability to define the molecule in a food to which a patient has significant specific IgE, and therefore provide diagnostic and prognostic information for patients with serious food allergy.

Specific IgE Testing Specific IgE is usually measured to confirm an allergic aetiology for symptoms when there is a history that suggests a possible allergic cause. All our specific IgE testing is performed on the Phadia ImmunoCAP 250 and Phadia ImmunoCAP 1000 system. As the majority of published studies in allergy use this testing method, it is widely considered the benchmark for quantifying specific IgE. An advantage of the Phadia ImmunoCAP system is that, for certain key foods, the 95% probability of a positive food challenge has been determined for certain levels of allergen-specific IgE in some populations (see Table 1). We will continue to report allergen specific IgE values in kU/L and a semiquantitative class value. Please note that some patients with a “negative” or “0” class may have detectable traces of specific IgE (0.10 to 0.35kU/L) that can have clinical significance as a marker of early sensitisation or previous significant sensitisation to insect venoms and drugs. We differentiate the allergens we can test for as single allergens (a mixture of allergens molecules from one source, for example milk, coded f2); mixed allergens (a mixture of allergens from several sources, for example staple foods, coded fx5 which includes egg white, cow’s milk, peanut, soy, wheat and codfish) and allergen components which are individual allergen molecules obtained by purification of the allergen molecule from a single source or by recombinant genetic technology, for example, the major milk components alpha-lactalbumin (coded f76), beta-lactoglobulin (coded f77) and casein (coded f78). Mixed allergens are useful to screen economically for sensitisation to allergens in a mix; Single allergens are useful to confirm sensitisation to particular allergens while allergen component testing can provide additional diagnostic and prognostic information about a person’s allergic sensitisation. Multiple components may be tested more economically and efficiently by the ISAC system when more than a few component allergens are of clinical interest. ISAC Microarray Technology In the most important practical advance in laboratory allergy diagnostics, the Phadia ImmunoCAP ISAC microarray system allows us to determine a patient’s specific IgE to 112 clinically important allergen molecules from 51 different allergens. Tests that define the molecule in a food to which a patient has significant specific IgE, can provide diagnostic and prognostic information for patients with serious food allergy. The ISAC profile is particularly useful for the assessment of highly sensitised patients, persons with birch tree pollen or other pollen cross-reactive oral allergy symptoms. The analytical sensitivity of the ISAC system for allergen-specific IgE detected by the ISAC profile is less than that of individual ImmunoCAPs and some lower level sensitisations may not be be detected by the ISAC profile. Similarly some persons may be sensitised to minor allergens in plants or foods that are not represented and therefore not detected by the ISAC system.

„ All our specific IgE testing is performed on the Phadia ImmunoCAP 250 and Phadia ImmunoCAP 1000 system. As the majority of published studies in allergy use this testing method, it is widely considered the benchmark for quantifying specific IgE. „

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