1. Determine the appropriate shelf life of WB that has been leukoreduced with a platelet sparing filter by measuring changes in levels of coagulation factors and global clotting potential of banked units over time. To accomplish this the investigators will measure variables known to reflect potential and actual clotting capacity including platelet function and overall clotting ability by thromboelastography (TEG) and thrombin generation analysis in whole blood up to 35 days.