D2.82 - Analytical Performance Evaluation of Cor a 8, Cor a 9, and Cor a 14 Hazelnut Components on IMMULITE 2000 XPi*

Tree nut allergy may affect up to 1.5% of people in Europe. In hazelnut allergy, Cor a 9 (11S globulin) and Cor a 14 (2S albumin) are strongly associated with severe reactions and the primary hazelnut allergy in children. Cor a 8, a non-specific lipid transfer protein, is more prevalent in Mediterranean regions and linked to cross-reactivity with peach (Pru p 3). While Cor a 1 dominates sensitization rates, specific IgE (sIgE) to Cor a 9 and Cor a 14 are considered to provide the highest diagnostic accuracy in children. In this study, we report the analytical performance of the newly developed  3gAllergy hazelnut components rCor a 8, nCor a 9, and rCor a 14 on the IMMULITE 2000 XPi system.

Limit of Blank (LoB), Limit of Detection (LoD), and Limit of Quantitation (LoQ) were determined per CLSI EP17-A2 for each allergen using replicate samples. Detection was determined using 2 reagent lots and a single analyzer per study. The highest calculated LoB/LoD/LoQ is reported. Linearity was assessed following CLSI ILA20 guidelines using serum pools diluted across the analytical range; data were analyzed by regression analysis. Method comparison followed CLSI EP09-A3, evaluating IMMULITE 2000 XPi results against a predicate device using 50 negative and 30 positive samples; agreement was determined by concordance analysis.

LoB, LoD, and LoQ values were 0.068 / 0.094 / 0.132 kU/L for rCor a 8, 0.022 / 0.041 / 0.086 kU/L for nCor a 9, and 0.041 / 0.063 / 0.066 kU/L for rCor a 14, respectively. Linearity was demonstrated across clinically relevant ranges:  rCor a 8 = 0.080 to 0.9 kU/L, Cor a 9 = 0.035  to 87.7 kU/L, and Cor a 14 = 0.051 to 89.2 kU/L. Method comparison showed strong agreement with predicate devices: rCor a 8 and rCor a 14 achieved 96.7% positive and 100% negative agreement (98.8% overall), while nCor a 9 achieved 100% for both, confirming strong agreement.

The allergens showed expected detection limits, appropriate linearity, and strong agreement with a reference method. These results confirm the assay’s sensitivity, precision, and reliability, supporting its suitability for routine clinical use in allergy diagnostics.