ABSTRACT
BACKGROUND: An essential prerequisite for successful procurement of sufficient peripheral blood stem cells (PBSC) for engraftment is the optimal timing of collection. The Sysmex SE-9000 automated hematology analyzer provides the immature information (IMI) channel for the identification and counting PBSC. In this study, The optimal timing of PBSC collection was studied using IMI channel. METHODS: 193 peripheral blood stem cell collections were performed from 52 patients with hematologic disorders or solid tumors and 15 donors. Pre-harvest peripheral blood WBC, mononuclear cells (MNC) and IMI were tested and compared with CD34+ cell count and CFU-GM count of harvested products. RESULTS: Peripheral blood WBC and MNC count showed a weak correlation with CD34+ cell yield (r=0.38, P1x10(6)/kg with sensitivity of 88.7%. Positive and negative predictive values of IMI >465/microliter for CD34+ cell >1x10(6)/kg were 65.5% and 87.5%, respectively. CONCLUSIONS: The automated IMI might be used as a simple and efficient indicator of PBSC mobilization and applying variable cutoff values of IMI would be a useful tool to predict the optimal timing of PBSC collection.