title: Comparison of three methods of CD34+ cell enumeration in peripheral blood: dual-platform ISHAGE protocol versus single-platform, versus microvolume fluorimetry.
abstract: BACKGROUND
  Quantitation of peripheral blood (PB) CD34(+) cells is now an established method for timing PBPC harvesting. Recent refinements to the dual-platform ISHAGE gating strategy for CD34(+) cells has seen the introduction of microbeads to enable absolute counting of cells on a single instrument platform. This eliminates the need for total WBCC performed on an automated hematology analyzer and potentially increases the analytical precision of the methodology. At the same time, alternative methods for CD34(+) cell enumeration have started to emerge, notably microvolume fluorimetry, which forms the basis of the fully-automated STELLer CD34 method using the Imagn 2000.
  
  
  METHODS
  We performed a three-way evaluation of these methods. Sixty-eight samples of PB from 42 patients undergoing PBPC mobilization were analyzed by all three methods and correlations between all three calculated. The two-platform ISHAGE method was used as the reference method.
  
  
  RESULTS
  Precision and linearity of the single-platform and STELLer CD34 assays were excellent. Correlation with the dual-platform reference method was also excellent (single-platform method slope = 1.03, intercept = -0.03 and R(2) = 0.9325, STELLer CD34 assay slope = 0.827, intercept = 4.27, R(2) =0.8215). Bias, determined by Bland-Altman analysis, was 1.16 and -1.62 for single platform and STELLer CD34 assay respectively.
  
  
  CONCLUSIONS
  The three methods of CD34(+) cell enumeration gave equivalent results. The single-platform methodology negated the need for a separate white cell analyzer, while the STELLer CD34 methodology was technically the simplest.
authors.affiliation: Blood and Marrow Transplant Service and Department of Pathology, Division of Hematology and Medical Oncology, Peter McCallum Cancer Institute, Melbourne, Victoria, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Chapple
authors.forename: H M
authors.initials: HM
authors.lastname: Prince
authors.forename: D
authors.initials: D
authors.lastname: Wall
authors.forename: R
authors.initials: R
authors.lastname: Filshie
authors.forename: D
authors.initials: D
authors.lastname: Haylock
authors.forename: M
authors.initials: M
authors.lastname: Quinn
authors.forename: M
authors.initials: M
authors.lastname: Bretell
authors.forename: D
authors.initials: D
authors.lastname: Venter
mesh_terms: D018952:Antigens, CD34 / Q000097:blood*; D001772:Blood Cell Count / Q000379:methods*; D001773:Blood Cells / Q000166:cytology / Q000276:immunology; D005470:Fluorometry / Q000379:methods*; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods*; D006801:Humans; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity
chemical_list: D018952:Antigens, CD34