Beckman Coulter's IntraPrep Permeabilization Reagent is a fixation and permeabilization reagent for use in flow cytometry sample preparation prior to intracellular staining. It contains formaldehyde to crosslink and fix cellular proteins. It also contains saponin to permeabilize cell membranes. This allows antibodies to enter cells and bind to intracellular antigens for immunophenotyping via flow cytometry. The reagent comes in a 500 mL bottle and is stable until the expiration date when stored at 2-8°C. It is compatible with common fluorochromes and can be used with whole blood, bone marrow, PBMCs, and cultured cells.