Young red cell preparation--a comparison of available methods.

Four possible methods of preparing young red cells (YRBC) which exploit the relationship between red cell ageing and density are compared. Of these, two cell separators and the IBM cell washer are shown to be capable of producing YRBC suitable for clinical use. YRBC prepared from the IBM 2991 cell washer are recommended for clinical trials because of lower cost, greater convenience and lower white cell contamination compared to cell separator-derived YRBC.