Table 1.

Comparison of Measurement Uncertainty Using Trucount and Volumetric Methods

Data set	Participant range (CD34 cells/μL)	Weighed mean value (CD34 cells/μL)	Uncertainty of mean value (CD34 cells/μL)
CD34 High, Trucount	19.2–34.5	26.2	0.9
CD34 Low, Trucount	6.2–10.8	8.6	0.4
CD34 High, volumetric	16.9–34.5	26.0	1.5
CD34 Low, volumetric	6.2–10.6	8.1	0.5

The table depicts the uncertainty of measurement estimate for CD34 cell concentrations obtained using either the Trucount method or the volumetric method. The components taken into account in the estimate were the variability within a batch of Trucount beads and the variability in sample preparation volumes recorded gravimetically at each stage of sample processing.