The DELFIA® BATDA Reagent is intended for labeling of cells to be used in short term cytotoxicity tests performe utilizing time-resolved fluorometry in the detection. It forms part of the AD0116 DELFIA® EuTDA Cytotoxicity Reagents pack, but is also available as an individual product. The individually available DELFIA BATDA labeling reagent is sufficient for 10x96 wells. DELFIA cytotoxicity assays offer a non-radioactive method to be used in cell mediated cytotoxicity studies. The method is based on loading cells with an acetoxymethyl ester of a fluorescence enhancing ligand. After the ligand has penetrated the cell membrane the ester bonds are hydrolyzed within the cell to form a hydrophilic ligand, which no longer passes through the membrane. After cytolysis the released ligand is introduced to a europium solution to form a fluorescent chelate. The measured signal correlates directly with the amount of lysed cells.