Analysis of the Optimal Blood Sampling Conditions for Estimation of Hematopoietic Progenitor Cell Count by the SE-9000 Automated Hematolyzer

Abstract

We evaluated the optimal conditions for blood sampling for hematopoietic progenitor cells (HPCs) as estimated by the immature information program of the SE-9000 automated hematology analyzer. The HPC count was most stable when the blood samples were incubated at room temperature with ethylene-diaminetetraacetic acid dipotassium (EDTA-2K) as an anticoagulant. The HPC count should, however, be measured within 4 h after blood collection, even under optimal conditions. In contrast, the CD34+ cell count estimated by flow cytometric analysis was stable for at least 21 h after the blood samples were incubated with EDTA-2K at room temperature or 4°C. When appropriate blood samples were used, the HPC count in the peripheral blood significantly correlated with the CD34+ cell count in the peripheral blood and in the apheresis yields (r = 0.798 and 0.635, respectively); therefore, the HPC count is a reliable predictor for initiation of apheresis procedures to obtain sufficient HPCs for peripheral blood stem cell transplantation.

Algorithms utilizing peripheral blood hematopoietic progenitor cell counts in lieu of some CD34+ cell counts predict successful peripheral blood stem cell collections with substantial time and cost savings

“…The correlation between PB CD34+ cell counts and HPC counts has shown much variability from study to study. Although most prior studies have shown that HPC counts are generally 1·5–4·0 times higher than PB CD34+ cell counts , in our laboratory, the HPC counts were generally less than the PB CD34+ cell counts (HPC median = 4 cells/ μ l vs. CD34+ median = 26·9 cells/ μ l) which also has been reported previously . The reason for these differences is likely multifactorial.…”

“…b) for cytokine‐mobilized patient samples ( n = 21). These are comparable to R values that have been reported in the literature for comparison of HPC vs. PB CD34+ cells .…”

“…The use of HPC to predict PB CD34+ cell counts and potentially guide PBSC collection has been proposed in the literature multiple times over the past two decades. Several groups have demonstrated reasonably good correlations between HPC counts and PB CD34 counts . Algorithms to guide PBSC collections using HPC counts have been proposed for certain patient populations .…”

“…Peripheral blood CD34+ quantification requires flow cytometry and generally requires two or more hours from draw time to result. A hematopoietic progenitor cell (HPC) count performed on an automated instrument (Sysmex) has become an attractive alternative to PB CD34+ cell quantification, and numerous studies have investigated its use in predicting CD34+ product yield [7][8][9][10][11][12][13][14][15][16]. This automated method involves quantifying immature hematopoietic cells, which have less lipid in the cell membranes and are thus less susceptible to lysis by a proprietary surfactant [10].…”