[The platelet/leukocyte ratio in red blood cell concentrates is an essential indicator of leukocyte removal filter efficiency which limits their use]. / Le rapport plaquettes/globules blancs dans les concentrés de globules rouges est un élément essentiel de l'efficacité des filtres à déleucocyter qui limite leur utilisation.

Performances of filter systems for leucocyte removal (Pall BPF4 and Sepacell RZ 200 B) have been studied following the preparation of red blood cell concentrates (RBCCs) obtained either by a soft-spin centrifugation at 2967xg (n = 438) or by a hard-spin centrifugation at 5275xg (n = 187). After deleucocytation, 43, i.e., 9.8% of RBCCs obtained following a soft-spin centrifugation contained a number of residual leucocytes higher than 1 x 10(6) leucocytes/RBCC which represents the legal upper limit in France, whereas RBCCs obtained following a hard-spin centrifugation always contained a number of residual leucocytes lower than this limit. Our results strongly suggest that the quality of deleucocytation depends on an adequate ratio of platelets to leucocytes, which favours the capture of leucocytes by filters. In fact, this ratio was higher in RBCCs obtained following a hard-spin centrifugation. Our results demonstrate that the use of these filters does not allow the removal of leucocytes complying with the legal limit of leucodepletion for all preparations of RBCCs.