Apoptosis generally refers to a process of programmed cell death that occurs during the process of apoptosis or under the action of certain factors through the regulation of intracellular genes and their products. Apoptosis can be divided into four stages based on theirselves characteristics, including early apoptosis, early middle apoptosis, middle late apoptosis and late apoptosis. As a life science tools manufacturer, Yeasen supplies complete solutions of early and late apoptosis detection based on the characteristics of these stages. Phosphatidylserine (PS) on the outer membrane of cells is usually detected by Annexin-V/PI double staining at the early stage of apoptosis. Late apoptosis is usually detected by the TUNEL method, which is also called terminal -deoxynucleotidyl transferase mediated nick end labeling.