Preparation of platelet (plt) concentrates from whole blood. Two methods of preparing plt concentrates from whole blood have been developed. The main differences are related to the centrifugation steps that are used when proceeding from whole blood to a plt concentrate. Specific details of the methods are described in Slichter and Harker¹ for plt-rich plasma (PRP) method plt concentrates and Pietersz et al² for buffy coat (BC) method plt concentrates.