Quality control for the cryopreservation of thousands of units of placental/umbilical cord blood (PCB) is a difficult problem in cord blood banking. The Bio Archive System (BA) is a liquid nitrogen freezer tank equipped with a computer for controlled-rate freezing and a robotic arm for insertion and retrieval of the units. It is designed for the cryopreservation of up to 3, 626 units of PCB. Leukocyte concentrates prepared by the hydroxyethyl starch method were expressed into freezing bags, with large and small compartments, and then frozen and stored in the BA. The recoveries of CD34 positive cells in the large and small compartments were 95.1±9.6% and 93.5±1.6%, respectively (n=8) and the recoveries of colony-forming cell were 99.6±18.5% and 115.8±27.8%, respectively. The results indicate that the BA is useful for controlled cryopreservation of PCB in cord blood banking.
