This workshop aims to address challenges and opportunities for the fit-for-purpose design and standardization of assays used in the characterization of cells (e.g. viability assays, cell count measurements, and functional assays). The discussion will span measurement platforms including techniques such as imaging cytometry counting, automated count and viability analyzers, biophysical property characterization and flow cytometry. These discussions will support ongoing pre-standardization and standardization efforts for documentary standards as well as the development of fit-for-purpose reference materials.