Background aims: Volume reduction is the usual process in cord blood banking that has some advantages regarding reducing the storage space and dimethyl sulfoxide (DMSO) quantity in the final product. The volume reduction methodology must guarantee high cell recovery and red blood cell (RBC) depletion by reducing all the umbilical cord blood (UCB) units to a standard volume.
Methods: We analyzed and compared critically three different volume reduction methods [hydroxyethylstarch (HES), top and bottom with Optipress II and Compomat G4, and AXP] used at the Valencia Cord Blood Bank over 10 years.
Results: The highest significant RBC depletion was achieved with the AXP system (P<0.001), while the top and bottom system with Compomat G4 and an adjusted buffy coat (BC) volume to 41 mL enabled the best total nucleated cell (TNC) recovery (P<0.001). TNC recovery and RBC depletion were similar for AXP and HES with an adjusted volume to 21 mL. In the multivariate analysis, when analyzing all cases, the BC volume set significantly influenced TNC, CD34+ and lymphocyte recoveries and RBC depletion (P<0.001). RBC depletion was significantly influenced by the initial volume and initial RBC content of UCB units (P<0.001).
Conclusions: AXP is a highly efficient method for RBC depletion, providing the same TNC recovery as HES method with a final volume of 41 mL. AXP has the advantages of being an automatic and functionally closed system that shortens and better standardizes the proceedings. Top and bottom is a closed system that allows better TNC recoveries when the BC volume set is 41 mL.