Drug hypersensitivity reactions (DHR) to platinum-based compounds (PC) are on the rise, and their personalized and safe management is essential to enable first-line treatment of these cancer patients. This study aimed to evaluate the usefulness of basophil activation test by flow cytometry (BAT-FC) and the newly developed sIgE-microarray and BAT-microarray in diagnosing IgE-mediated hypersensitivity reactions to PC. 24 patients with DHR to PC (20 oxaliplatin and four carboplatin) were evaluated: 13 patients diagnosed as allergic with positive skin tests (STs) or drug provocation tests (DPTs), six patients diagnosed as non-allergic with negative STs and DPTs, and five patients classified as suspected allergic because DPTs could not be performed. In addition, four carboplatin-tolerant patients were included as controls. BAT-FC was positive in 2 of 13 allergic patients, with a sensitivity of 15.4% and specificity of 100%. However, the sIgE- and BAT-microarrays were positive in 11 of 13 DHR patients, giving a sensitivity of over 84.6% and a specificity of 90%. Except for one patient, all samples from the non-allergic and control group were negative for the sIgE- and BAT-microarrays. Our experience indicates that sIgE- and BAT-microarray could be helpful in the endophenotyping of IgE-mediated hypersensitivity reactions to PC and may provide an advance in decision-making for drug provocation testing.