Biopharmaceuticals are highly complex molecules in which even the smallest changes can lead to altered biological activity, also known as potency. For this reason, at least one bioassay is included in the specification in addition to the physicochemical analyses. These assays test the efficacy either close to the biological system, e.g. in an enzyme-linked immunosorbent assay (ELISA), or directly in the biological system, in living cells, so-called cell-based bioassays. Our specialised bioassay group analyses samples from stability studies and release tests, up to large work packages with several hundred samples with the same diligence and the highest quality standards. Our services include the management, if necessary, the procurement and qualification of cell cultures and critical reagents. We have extensive experience with the transfer of already validated assays to our laboratory, and also with the optimisation and subsequent validation of bioassays from early development phases.