Breadcrumb Home Propidium Iodide for Viability Reagents Propidium Iodide (ThermoFisher cat# P1304MP 100mg powder) 1X PBS Stock 50µg/ml in 1X PBS Staining Dilute stock 50:1 in cell suspension for final dilution of 1µg/ml (e.g. add 20µl of stock solution to 1ml of cell suspension). Add just before running on flow cytometer.