BD FACSCalibur - Precision

Appendix C: Performance Data 227
Precision
Two studies were conducted to assess within-specimen reproducibility: one using
BD Multitest CD3/CD8/CD45/CD4 + BD Trucount reagent; the other using
BD Multitest CD3/CD16+CD56/CD45/CD19 + BD Trucount reagent. All testing
was performed on the BD FACSCalibur instrument.
For both studies, estimates of within-sample reproducibility were determined at 3
clinical laboratories from 5 replicates of each sample collected from normal and
abnormal donors. Replicates which did not pass QC, and those where no data
was acquired, were excluded from the study.
Means, standard deviations (SD), and/or coefficients of variation (CV) are
provided for subset percentages and absolute counts greater than 100 cells/
µL in
Tables C-2 and C-3 and Tables C-4 and C-5.
Table C-2 Within-specimen reproducibility of subset percentages
(BD Multitest CD3/CD8/CD45/CD4)
Subset n
a
a. Number of samples
Mean (%) SD
Helper/inducer T lymphocytes (%) 46 26.1 0.85
Suppressor/cytotoxic T lymphocytes (%) 46 42.0 0.93
Total T lymphocytes (%) 46 72.0 1.06
Table C-3 Within-specimen reproducibility of absolute counts
(BD Multitest CD3/CD8/CD45/CD4)
Subset n
Mean
(cells/µL)
SD % CV
Helper/inducer T lymphocytes (cells/µL) 38 565.2 62.92 7.02
Suppressor/cytotoxic T lymphocytes (cells/µL) 46 687.8 54.02 6.79
Total T lymphocytes (cells/µL) 46 1219.9 101.57 6.34