Agreement between allergen-specific IgE assays and ensuing immunotherapy recommendations from four commercial laboratories in the USA

BACKGROUND: Canine allergen-specific IgE assays in the USA are not subjected to an independent laboratory reliability monitoring programme. HYPOTHESIS/OBJECTIVES: The aim of this study was to evaluate the agreement of diagnostic results and treatment recommendations of four serum IgE assays commercially available in the USA. METHODS: Replicate serum samples from 10 atopic dogs were submitted to each of four laboratories for allergen-specific IgE assays (ACTT®, VARL Liquid Gold, ALLERCEPT® and Greer® Aller-g-complete®). The interlaboratory agreement of standard, regional panels and ensuing treatment recommendations were analysed with the kappa statistic (κ) to account for agreement that might occur merely by chance. Six comparisons of pairs of laboratories and overall agreement among laboratories were analysed for ungrouped allergens (as tested) and also with allergens grouped according to reported cross-reactivity and taxonomy. RESULTS: The overall chance-corrected agreement of the positive/negative test results for ungrouped and grouped allergens was slight (κ = 0.14 and 0.13, respectively). Subset analysis of the laboratory pair with the highest level of diagnostic agreement (κ = 0.36) found slight agreement (κ = 0.13) for ungrouped plants and fungi, but substantial agreement (κ = 0.71) for ungrouped mites. The overall agreement of the treatment recommendations was slight (κ = 0.11). Altogether, 85.1% of ungrouped allergen treatment recommendations were unique to one laboratory or another. CONCLUSIONS AND CLINICAL IMPORTANCE: Our study indicated that the choice of IgE assay may have a major influence on the positive/negative results and ensuing treatment recommendations. [Image: see text] [Image: see text]