Harmonization of cytometry instrumentation and technologies

Evaluation and validation of a novel 10-color flow cytometer

Background

Flow cytometry is a powerful technique that provides information regarding cell properties. In this study, we evaluated the analytical performance of a new flow cytometer, the 10‐color BD FACSLyric^TM, which could help doctors obtain reliable test results prior to clinical research.

Methods

We used Sphero^TM Rainbow Calibration Particles and the Sphero^TM Nano Fluorescent Particle Size Standard Kit to validate the fluorescence sensitivity and linearity. The Beckman Coulter IMMUNO‐TROL Cell was used as the quality control to evaluate the accuracy and reproducibility of surface markers detected by the flow cytometer. Furthermore, BD Calibrate APC Beads and CS&T Research Beads were applied to calculate the carry‐over contamination rate and assess the instrument stability.

Results

A linear regression equation between the molecules of equivalent soluble fluorochrome and fluorescence detection limit showed a good linear fit (R² > 0.99). The minimum bead size detected by side scatter was 0.22 μm. The coefficient of variation percentage of each fluorescence channel was below 2%, and the carry‐over contamination rate of the cytometer was under 0.2%. After running the BD FACSLyric^TM cytometer continuously for 8 h, the median fluorescence index of particles remained close to that at the time of cytometer startup.

Conclusions

The 10‐color BD FACSLyric^TM cytometer showed good performance in the evaluation performed in this study and may be trusted to provide accurate results for clinical research.

Evaluation of a novel automated volumetric flow cytometer for absolute CD4+ T lymphocyte quantitation

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 ρ_c  = 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.