The critical and unique feature is that the xCELLigence System detects cell responses throughout an experiment, enabling discovery not possible with endpoint assays. The xCelligence System provides improved, real-time, label free and non-invasive analyses of key cellular events with an impedance based cell sensing measurement system. The System consists of an analyzer that can fit on one half of one shelf of a standard cell culture incubator. The analyzer has slots for three specialized plates containing 16 wells each. Therefore, up to 48 conditions or treatments can be monitored at one time. Applications include: Cell invasion and migration assays, Compound- and cell-mediated cytotoxicity, Cell adhesion and cell spreading, Cell proliferation and cell differentiation, Receptor-mediated signaling, Virus-mediated cytopathogenicity.