Luminescence-Based Cell Viability Testing

There are many reasons for testing cell viability. Simple tinctorial assays, such as trypan blue exclusion, have their place, but luminescence assays based on the detection of adenosine triphosphate (ATP) are particularly useful, since it is possible to detect the ATP present in fewer than 20 cells/mL using optimized reagents. These same reagents can also accurately determine the ATP from 2 � 10⁷ cells/mL in an adjacent well or test tube with a completely linear relationship between cell number and light output, provided that the cells maintain a relatively invariant ATP content. Similar methods are used for bacteria and eukaryotic cells, but this chapter is restricted to the consideration of eukaryotic cells. Luminescence measurement of ATP levels uses the following reaction: