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BACKGROUND: Bead-based single platform cytometry technology (SPT) is the gold standard when performing CD4 absolute counting. However, it presents drawbacks as precision depends on various critical steps (for example, pipetting methodology, overtime stability of beads, stability of fluidics, regular recalibration…) and thus requires skilled operators. The fully automated volumetric SPT AQUIOS CL (Beckman Coulter) has recently emerged as an alternative with no need of beads. It may help improving results standardisation and fulfilling requirements for certification (ISO 15189). In this study, we assessed SPT AQUIOS CL performances in accordance to requirements for ISO 15189 accreditation. METHODS: We evaluated repeatability and reproducibility (precision), bias (trueness), uncertainty (total error), range limits (linearity, quantification, detection limits), and inter-reagent/inter-sample contaminations in enumerating CD4+ T-cells. Concomitantly, we compared AQUIOS CL CD4+ T-cell values with the results obtained with our routine bead-based SPT (that is, FC500 Beckman Coulter, bead-based SPT), on blood samples from 148 patients representative of clinical laboratory routine workload. RESULTS: Every result (repeatability, reproducibility, trueness, total error) was below the acceptable thresholds proposed in international recommendations. Contamination results and range limits (linearity, quantification, and detection limits) were all found perfectly suitable to routine analysis. The comparison between AQUIOS CL and FC500 exhibited excellent correlation and agreement (Pearson R = 0.99, P < 0.001; Lin's concordance correlation coefficient: Lin ρc  = 0.991, Cb = 0.999), and Bland-Altman analysis did not reveal any systematic error. CONCLUSIONS: Our results demonstrate that, upon subsequent validation in more routine conditions, the AQUIOS CL could be a suitable tool for clinical flow cytometry laboratories facing accreditation process. © 2016 International Clinical Cytometry Society.

Original publication




Journal article


Cytometry B Clin Cytom

Publication Date





456 - 464


CD4; AQUIOS; absolute count; flow cytometry, Adolescent, Adult, Aged, Aged, 80 and over, Autoimmune Diseases, Automation, Laboratory, Biomarkers, CD3 Complex, CD4 Lymphocyte Count, CD4-Positive T-Lymphocytes, Child, Child, Preschool, Flow Cytometry, HIV Infections, Hematologic Neoplasms, Humans, Immunophenotyping, Infant, Leukocyte Common Antigens, Limit of Detection, Middle Aged, Reproducibility of Results, T-Lymphocyte Subsets