The M65® ELISA measures soluble keratin 18 released from dying cells and can be used to assess total cell death due to apoptosis and necrosis. The assay is primarily intended to be used together with the M30 Apoptosense® ELISA, which specifically measures apoptosis. When used together, the quantification of total cell death, apoptosis and necrosis is possible. As both assays are calibrated against the identical reference, the combination of M30 Apoptosense® ELISA and M65® ELISA should allow determining the relative contribution of apoptosis to the total degree of cell death. M65® ELISA is intended for human sera, and is CE marked as a medical device for in vitro diagnostic use.