The assay is designed to detect ADP/ATP ratio. The changes in ADP/ATP ratios have been used to conveniently differentiate apoptosis from necrosis.

The assay utilizes bioluminescent detection of ADP and ATP levels for rapid screening of apoptosis (TUNEL-based techniques and caspase assays), necrosis, growth arrest and cell proliferation simultaneously in mammalian cells. The assay utilizes the enzyme luciferase to catalyze the formation of light fom ATP and luciferin. The light can be measured using a luminometer or beta counter. ADP levels are measured by its conversion to ATP that is subsequently detected using the same reaction.

This highly sensitive assay (detects 100 mammalian cells/well) can be fully automated for high throughput measurements.