Cell in well is a proprietary technology that generates stocks of large number of frozen cells already seeded in microplates. The straight use of cells frozen in microplates within screening campaigns implies not only the convenience of a ready-to-use assay but many other advantages that have to do with assay standardization. Cells from the same batch are harvested with the same passage number, at the same growth phase and are subject to the same freezing/thawing conditions along with a low dispersion number of cells among wells at seeding. Microplates from the same batch can be stored for later use at different time points reducing the assay-to-assay variability.