Primed for change: The effect of a blood prime on peripheral blood stem cell collection and accuracy of a prediction tool in pediatric patients.

Pediatric apheresis collection of peripheral blood stem cells for autologous transplantation often requires use of a blood prime. We evaluated the relationship between pre-apheresis blood CD34 counts and final CD34 yield with use of a blood prime. Forty patients underwent apheresis stem cell collection in a 5 year period in our hospital, of which 27 required blood priming of the apheresis machine. Despite the blood prime group having significantly higher pre-apheresis CD34 cell counts, this group processed a relatively higher volume of blood due to a higher dilutional effect and collected significantly less than predicted CD34 cell yield. Use of weight-specific collection efficiencies and dilution-adjusted pre-apheresis CD34 counts will help in accurately estimating the whole blood volume to process for PBSC collection and therefore increase efficiency and decrease the overall cost of collection.