Preparation of packed red blood cell units in the blood bank: Alteration in red blood cell deformability.

Background: Donated blood is stored in the blood bank as packed red blood cell units. In the process of packed cells preparation, the red blood cells (RBCs) are subjectedto high level of shear stress, which can induce alterations in their properties. In the present study, we examined the effect of packed RBCs preparation (which included leuko-filtration) on red cell deformability. Methods: Blood samples were collected from 25 healthy donors and from corresponding units of packed RBCs. The portion of undeformable cells (%UDFC) was determined for each sample. Results: The median value of %UDFC was equal to 6.75 +/- 0.70 %, for freshly-donated RBCs, and to 6.36 +/- 0.51 %, for packed cells. Wherein, %UDFC may increase or decrease following packed cells preparation, depending upon the initial portion of undeformable cells. Conclusion: Likely, exposure of RBCs to high shear stress, during packed cells preparation, induces opposing effects: (a) removal/destruction of rigid (undeformable) cells, thereby reducing their total amount (i.e., decreasing the %UDFC) on the one hand, and (b) mechanical damage to the cell membrane and subsequent reduction of the cell deformability (thereby increasing the %UDFC) on the other. As a consequence, the final impact of packed cells preparation is primarily determined by the initial state of erythrocytes in the blood of the donor.