Multi-site evaluation of the BD Stem Cell Enumeration Kit for CD34(+) cell enumeration on the BD FACSCanto II and BD FACSCalibur flow cytometers.

Background Aims: Evaluation of the BD Stem Cell Enumeration Kit was conducted at four clinical sites with flow cytometry CD34(+) enumeration to assess agreement between two investigational methods: (i) the BD FACSCanto II and BD FACSCalibur systems and (ii) the predicate method (Beckman Coulter StemKit and StemTrol, Immunotech SAS, Beckman Coulter, Marseille Cedex 9, France).

Methods: Leftover and delinked specimens (n = 1032) from clinical flow cytometry testing were analyzed on the BD FACSCanto II (n = 918) and BD FACSCalibur (n = 905) in normal and mobilized blood, frozen and thawed bone marrow and leucopheresis and cord blood anticoagulated with citrate phosphate dextrose, anticoagulant citrate dextrose-solution A, heparin and ethylenediaminetetraacetate, alone or in combination. Fresh leucopheresis analysis addressed site equivalency for sample preparation, testing and analysis.

Results: The mean relative bias showed agreement within predefined parameters for the BD FACSCanto II (-2.81 to 4.31 ±7.1) and BD FACSCalibur (-2.69 to 5.2 ±7.9). Results are reported as absolute and relative differences compared with the predicate for viable CD34(+), percentage of CD34(+) in CD45(+) and viable CD45(+) populations (or gates). Bias analyses of the distribution of the predicate low, mid and high bin values were done using BD FACSCanto II optimal gating and BD FACSCalibur manual gating for viable CD34(+), percentage of CD34(+) in CD45(+) and viable CD45(+). Bias results from both investigational methods show agreement. Deming regression analyses showed a linear relationship with R(2) > 0.92 for both investigational methods.

Discussion: In conclusion, the results from both investigational methods demonstrated agreement and equivalence with the predicate method for enumeration of absolute viable CD34(+), percentage of viable CD34(+) in CD45(+) and absolute viable CD45(+) populations.