Cell death or cytotoxicity is classically evaluated by the quantification of plasma membrane damage. Adenylate kinase (AK) is a ubiquitous protein present in all eukaryotic and prokaryotic cells and rapidly release into culture medium upon damage of the plasma membrane. The Bioluminescence Cytotoxicity Assay Kit is based on the measurement of AK in a simple one-step procedure involving two chemical reactions. The first reaction is the conversion of ADP to ATP by adenylate kinase that was released from the damaged cells. The second reaction utilizes luciferase to catalyze the formation of light from ATP and luciferin, and the light can be measured using a luminometer or beta counter. The assay is highly sensitive and can be fully automatic for high throughput.