Our Necrosis vs Apoptosis Assay kits simultaneously detects both apoptosis associated cytotoxicity events as well as cell death due to necrosis. Loss of the integrity of the cell membrane, indicative of necrosis or late stage apoptosis, is detected using the vital staining dye, 7-aminoactinomycin D (7-AAD), a red fluorescing live/dead stain. This dye easily penetrates cell membrane-compromised cells, binding tightly to GC rich regions of the DNA. Because 7-AAD alone may not detect cells in the early stages of apoptosis, it is essential to use it in combination with the green-fluorescent FAM-FLICA apoptosis detection reagent. Combining these two different types of fluorescent cell-status-indicator reagents within a single test can reveal a significant percentage of cells that are 7-AAD-negative (membrane intact live cells) and yet FAM-FLICA positive (apoptotic).