A newly developed filter for prestorage leucocyte depletion of platelet concentrates (PC) was studied. The filter is designed for leucocyte depletion during the preparation of the pool PC from platelet rich huffy coats. In all the leucocyte depleted PC (LD-PC) leucocyte depletion was satisfactory. 19 of 20 units of LD-PC had a leucocyte content below 3x10^5 per PC and 1 contained 8x10^5 leucocytes. The standard PC contained 2.53x10^8 (0.87x10^8-15.3x10^8; n = 20) leucocytes per PC (median and range). The quality of the LD-PC was evaluated by measuring platelet activation, platelet morphology, and pre- and poststorage pH. There were no differences in any of the parameters studied.