Aim of the studyThe aim is to compare the diagnostic performances of two multi-allergenic IgE microarrays of different composition and principle. Patients and methodsTwenty-one patients with polysensitivity or unexplained anaphylaxis were tested by two microarrays: the ISAC® biochip and the ALEX2® biochip. ResultsThe overall agreement of results between the two biochips was very good (97.8%), Analysis by molecular protein family shows a higher frequency of ALEX® positivity for LTP (7.4% versus 5.8 %), while the opposite is true for PR-10 (14.9% for ISAC® versus 11.9% for ALEX®). However, the concentrations observed in ALEX® for PR-10 are higher. As expected, a pretreatment by a specific inhibitor blocked the interference of anti-CCD IgE in ALEX® biochip. The analysis by patient allowed to highlight sensitizations to some specific components of each biochip: meat, fish, and pistachio present only on ALEX2® or alpha-Gal on ISAC®. ConclusionThe results obtained with the 2 biochips are generally consistent for common allergens. A more complete chip combining extracts as molecular allergens not available in individual tests should find its place in the exploration of unexplained anaphylaxis but the choice and number of allergens tested should evolve to best meet clinical needs.