Comparison of three methods of CD34(+) cell enumeration in peripheral blood: dual-platform ISHAGE protocol versus single-platform, versus microvolumefluorimetry

Background Quantitation of peripheral blood (PB) CD34(+) cells is now nn es tablished method for timing PBPC harvesting. Recent refinements to the dual -platform ISHAGE gating strategy for CD34(+) cells has seen the introductio n of microbeads to enable absolute counting of cells on a single instrument platform. This eliminates the need for total WBCC performed on an automate d hematology analyzer and potentially increases the analytical precision of the methodology! At the same time, alternative methods for CD34(+) cell en umeration have started to emerge, notably microvolume fluorimetry, which fo rms the basis of the fully-automated STELLer CD34 method using the Imagn 20 00. Methods We performed a three-way evaluation of these methods. Sixty-eight s amples of PB from 42 patients undergoing PBPC mobilization weve analyzed by all three methods and correlations between all three calculated. The two-p latform ISHAGE method was used as the reference method. Results Precision and linearity of the single-platform and STELLer CD34 ass ays 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 = 0.821 5). Bias, determined by Bland-Altman analysis, was 1.16 and -1.62 for singl e platform and STELLer CD34 assay respectively. Conclusion The three methods of CD34(+) cell enumeration gave equivalent re sults. The single-platform methodology negated the need for a separate whit e cell analyzer while the STELLer CD34 methodology was technically the simp lest.