Background aims: Stem cells are commonly enumerated with bead-based methods in blood and marrow progenitor cell transplantation centers. We compared the International Society of Hematotherapy and Graft Engineering (ISHAGE) bead-based method with a true volumetric one that obviates the use of fluorescent beads for enumeration.
Methods: From 31 samples, including 15 peripheral blood samples and 16 leukapheresis products, CD34 (+) cells were enumerated with the single-platform bead-based ISHAGE method and a true volumetric method. After exclusion of two outliers, one from the peripheral blood group and the other from the leukapheresis group, the results were compared.
Results: In the peripheral blood category, no significant difference was observed. However, a proportional systematic error was seen in the leukapheresis group. The systematic error was corrected in the leukapheresis group using a regression line equation. The 95% confidence interval of differences was [-5.83, 2.18] for the peripheral blood and [-38.40, 38.77] for the leukapheresis group after correction of the systematic error.
Conclusions: The true volumetric method is a simple and reliable approach that can be used instead of the more popular bead-based procedures.