<qa>  What is the most prevalent drug hypersensitivity to betalactams antibiotics?The COBIOPHAD project targets the development of a highly sensitive, selective, and multiplexed diagnostic device to provide a quick and inexpensive in vitro test to address the most prevalent drug hypersensitivity to betalactams antibiotics, BLCs. During a retrospective study, BLC structures involved in drug hypersensitivity will be identified from sera of allergic patients versus controls and coupled on the device. 