A comprehensive comparison between ISAC and ALEX² multiplex test systems

Area of Science:

• Allergy and Immunology
• Diagnostic Testing
• Molecular Diagnostics

Background:

• Type I hypersensitivity diagnosis relies on clinical history, provocation tests, and immunological assays.
• Multiplex specific IgE (sIgE) testing allows simultaneous detection of sIgE antibodies against numerous allergens.
• Evaluating novel diagnostic platforms is crucial for improving allergy diagnostics.

Purpose of the Study:

• To assess the performance of the ALEX 2 multiplex platform for allergy diagnostics.
• To compare the ALEX 2 test results with the established ImmunoCAP ISAC system.
• To determine the concordance and agreement metrics between the two sIgE testing platforms.

Main Methods:

• Serum samples from 49 patients with known ISAC results were analyzed using the ALEX 2 platform.
• Comparison involved 103 common allergen components present on both platforms.
• Statistical analysis included Cohen's kappa, negative percent agreement (NPA), and positive percent agreement (PPA).

Main Results:

• Overall agreement between ALEX 2 and ISAC was high at 94%.
• Negative percent agreement (NPA) was 95%, and positive percent agreement (PPA) was 90%.
• Kappa values ranged from 0.60 to 0.92, indicating moderate to almost perfect agreement; 59% of discrepancies involved weak positive results.

Conclusions:

• The ALEX 2 multiplex assay demonstrates high concordance with the ImmunoCAP ISAC system for common allergen components.
• The findings support the reliability of the ALEX 2 platform for sIgE testing in allergy diagnostics.
• Further investigation into discrepancies, particularly weak positive results, may refine clinical interpretation.