Product Description: Propidium Iodide (PI) is a ready-to-use cell viability dye for the exclusion of nonviable cells in flow cytometry analysis. The solution can be used in conjunction with fluorescein (FITC), cyanine-5 (CY5), and allophycocyanin (APC) conjugated Annexin V to distinguish cells that are in the early versus late stages of apoptosis. Excitation/emission – 536/617 nm