Comparison of Singleplex Specific IgE Detection Immunoassays: ImmunoCAP Phadia 250 and Immulite 2000 3gAllergy

Abstract

BackgroundThe identification of clinically meaningful specific immunoglobulin E (sIgE) is important for the diagnosis and management of allergic diseases. Various in vitro sIgE detection methods are available worldwide. Depending on the number of antigens that can be tested simultaneously, there are two representative methods: singleplex and multiplex. Singleplex sIgE detection is mainly provided by Thermo Fisher (ImmunoCAP) and Siemens (Immulite). This study aimed to compare the diagnostic agreement of two singleplex sIgE detection assays.MethodsSera from 209 Korean patients with allergic disease were used to compare the ImmunoCAP and Immulite assays with respect to the following allergens: inhalant allergens (Dermatophagoides farinae, cat and dog dander, oak, rye grass, mugwort, Alternaria, German cockroach) and food allergens (hen's egg white, cow's milk, wheat, peanut, soybean, and shrimp). Data from 902 paired comparison tests were included for comparisons. Qualitative, semi-quantitative, and quantitative comparisons were performed using statistical analyses.ResultsIn qualitative comparisons, the positivity and negativity agreements ranged from 75% (wheat, shrimp) to 96% (Alternaria). Class consistency (classes 0–6) was well matched. Spearman's rank correlation coefficients for all allergens except shrimp were over 0.7. In quantitative comparisons, all allergens excluding shrimp showed >0.7 intra-class correlation coefficients.ConclusionsThe ImmunoCAP and Immulite systems showed similar performances. However, clinicians should consider fundamental methodological differences between the assays.

Precision medicine allergy immunoassay methods for assessing immunoglobulin E sensitization to aeroallergen molecules

“…Based on sandwich fluoro-enzyme immunoassay method, ImmunoCAP FEIA offers the opportunity to assess the patient’s allergic sensitization profile not only for natural extracts but also at molecular level. It has several steps[ 42 , 44 , 53 - 55 ]: (1) Specific IgE binding to solid-phase step: Native purified or recombinant allergen component covalently coupled to a flexible solid-phase, with a large surface area, a highly branched, hydrophilic cellulose CNBr-activated polymer/sponge encased in a capsule or capsulated carrier polymer (ImmunoCAP with 1-2 µg allergen), reacts with the specific IgE from the patient plasma/serum sample; (2) Conjugate/labeled anti-IgE detection antibody step: After washing away unbound antibodies, β-galactosidase-labeled anti-IgE mouse monoclonal antibody is added to form the so-called antigen-antibody immune complex; and (3) Fluorescent signal step: After the unbound enzyme-anti-IgE is washed away, 4-methlyumbelliferyl-β-galactoside is used as a fluorogenic substrate, incubated with the bound complex to produce the fluorescent 4-methylumbelliferone. After stopping the reaction, the fluorescence measurement of the eluate is performed with a fluorocounter, and there is a correlation between fluorescence and the allergen-bound IgE established from a standard curve of concentration points.…”

“…LoQ for ImmunoCAP specific IgE is 0.1 kU A /L. The detection limits are 0.10-100 kU A /L[ 44 , 55 ]. In the ImmunoCAP system, 1 kU A /L specific IgE represents 0.994 kU/L total IgE, and is equal to 2.4 ng/mL specific IgE.…”

“…This new generation automated liquid-phase immunoassay was introduced in 2003. The use of fluid-phase allergens allows rapid binding kinetics between IgE and the allergenic protein conformations, and a time-to-first-result of only 65 min, while enzyme-enhanced chemiluminescence is used for optimal accuracy[ 43 , 55 ]. This automated quantitative chemiluminescent method can also be used in molecular allergy diagnostics.…”

Comparison of an automated microfluidic immunoassay technology (BioIC, lab-on-chips) and ImmunoCAP assay. Lab-on-chips as a tool for specific IgE (sIgE) detection

“…Thus, culinary culture and biogeographic characteristics should be taken into consideration when designing test panels [2,3]. Clinicians should also consider age of the patient, cross-reactivity of the allergen, exposure history with relevant manifestations in identifications of causative allergen(s) [4][5][6].…”

Allergen Microarrays forIn VitroDiagnostics of Allergies: Comparison with ImmunoCAP and AdvanSure

“…The once market-leading RAST method is no longer popular, since this is considered to be a rather inefficient and expensive method compared with others [ 4 ]. Thus, this assay has been replaced with the ImmunoCAP system as the generally accepted reference method as it provides an accurate and quality-controlled assay for the in vitro detection and measurement of sIgEs [ 5 6 7 ]. The CAP system uses a pool of a cellulose sponge matrix coated with mixture of allergen extracts or component allergens to capture sIgEs in the patient's serum, which are then detected using an enzyme-linked anti-IgE antibody via an enzymatic reaction [ 8 ].…”