title: Single- versus dual-platform assays for human CD34+ cell enumeration.
abstract: We comparatively assessed CD34+ cell quantification by two of the recently available single platform assays, the IMAGN 2000 STELLer (Immucor, Lisbon, Portugal) microvolume fluorimetry and the ProCOUNT (BD-ENZIfarma, Lisbon, Portugal) flow cytometry, with our "in-house" dual-platform flow cytometric assay. The performance of the methods was evaluated by linearity and reproducibility tests. The linearity study, over a range of 0-1,200 CD34+ cell/microl, gave a good linear relationship for the three methods, with R(2) > 0.99. Precision tested at three different concentrations gave coefficients of variation ranging from 3.6-26.4% for the STELLertrade mark, 2.4-13.8% for the ProCOUNT, and 3.2-6.4% for flow cytometry. CD34+ cells were quantified in umbilical cord blood (UCB), UCB enriched-leukocyte buffy-coat (BC), mobilized peripheral blood (PB) and mobilized peripheral blood progenitor cells (PBPC) collected by leucapheresis, from a total of 72 samples. Flow cytometric results showed good linear correlation to the absolute counts obtained by the STELLer and ProCOUNT for all samples (R > 0.90 for all methods), with no differences when compared by paired tests (P > 0.05). Linear correlations between methods were also found when individually looking at the different cell sources: UCB or PB, BC, and PBPC, with low, intermediate and high CD34+ cell concentrations, respectively. Furthermore, with the exception of a significant difference between the ProCOUNT and STELLer results for UCB (P < 0.05), no other difference between methods was found for each of the individual populations (P > 0.05). To our knowledge, this is the first report in which the results are presented and analyzed according to each source of CD34+ cells. Our results show that the STELLer and the ProCOUNT are equally efficient for the dual-platform flow cytometric assay in CD34+ cell quantification.
authors.affiliation: Instituto Português de Oncologia Francisco Gentil, Centro do Porto, Porto, Portugal.
authors.forename: I L
authors.initials: IL
authors.lastname: Barbosa
authors.forename: M E
authors.initials: ME
authors.lastname: Sousa
authors.forename: M I
authors.initials: MI
authors.lastname: Godinho
authors.forename: F
authors.initials: F
authors.lastname: Sousa
authors.forename: A
authors.initials: A
authors.lastname: Carvalhais
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism*; D001772:Blood Cell Count / Q000379:methods*; D005312:Fetal Blood / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D007962:Leukocytes / Q000378:metabolism; D011786:Quality Control; D015203:Reproducibility of Results
chemical_list: D018952:Antigens, CD34