Abstract Background:ImmunoCAP ISAC 112, is a commer-cially available molecular allergy IgE multiplex test. Data on the comparison of this rather novel test with extract-based as well as molecular Immuno-CAP singleplex IgE tests is missing. Objective:To perform a comparison between the ISAC multiplex IgE assay and the ImmunoCAP single plex test results. Methods:Serum samples of 101 adults with grass pollen allergy were analysed for sIgE to 112 aller-genic molecules represented on the ISAC test as well as to common atopy-related extract-based allergy tests with the ImmunoCAP System (house dust mite [d1], cat [e1], dog [e5], cow’s milk [f2], hen’s egg [f1], hazelnut [f17], celery [f85], Alternaria alternate [m6], as well as pollen from birch [t3], hazel [t4], mugwort [w6], and ragweed [w1]). Subsequently sta-tistical analysis was performed with the Spearman rank correlation test and the Clopper-Pearson
method in order to compare the ISAC multiplex results with the sIgE singleplex results.Results: e positive percent agreements (PPA) and negative percent agreement (NPA) of correspond-ing allergens between the ISAC sIgE test and the ex-tract-based singleplex ImmunoCAP results at cut-o 0.1 kUA/l varied between 60–100 % for PPA and 78–97 % for NPA. Conclusion:When taking into account correspond-ing allergens molecular testing with the ISAC multi-plex test correlates well with ImmunoCAP single-plex results