Regulatory Status Legend

Description

The Prodidium Iodide (PI) Staining Solution may be used to assess plasma membrane (PM) integrity in Annexin V apoptosis assays. PI is a fluorescent vital dye that stains DNA. It does not cross the PM of cells that are viable or in the early stages of apoptosis because they maintain PM integrity. In contrast those cells in the late stages of apoptosis or already dead have lost PM integrity and are permeable to PI. PI is detected in the orange range of the spectrum using a 562-588 nm band pass filter. Annexin V binds to cells early in apoptosis, and continues to be bound through cell death. PI is used in two-color Annexin V flow cytometric assays to distinguish cells that are in the earlier stages of apoptosis (Annexin V positive, PI negative) from those that are in the later stages of apoptosis or already dead (Annexin V positive, PI positive).