Abstract
Objectives
Flow cytometry analyses of lymphocyte subpopulations (T, B, NK) are crucial for enhancing clinical algorithms and research workflows. Estimating the total error (TE) values for the percentage and absolute number of lymphocyte subpopulations using the state-of-the-art (SOTA) approach with real data from an external proficiency testing (EPT) scheme was performed. A comparison with previously published Biological Variability (BV)-based specifications was carried out.
Methods
A total of 44,998 results from 86 laboratories over 10 years were analysed and divided into two five-year periods (2012–2016) and (2017–2021). Data come from the IC-1 Lymphocytes scheme of the Spanish External Quality Assurance System (EQAS) GECLID Program. This quantitative scheme includes percentages and absolute numbers of CD3+, CD3+CD4+, CD3+CD8+, CD19+, and CD3−CD56+CD16+ NK cells. The percentage of TE was calculated as: |reported value − robust mean|*100/robust mean for each laboratory and parameter. The cut-off for TE is set at 80 % best results of the laboratories.
Results
A significant reduction in the SOTA-based TE for all lymphocyte subpopulations in 2017–2021 was observed compared to 2012–2016. The SOTA-based TE fulfils the minimum BV-based TE for percentages of lymphocyte subpopulations. The parameter with the best analytical performance calculated with SOTA (2017–2021 period)-based TE was the percentage of CD3+ (TE=3.65 %).
Conclusions
The values of SOTA-based specifications from external quality assurance program data are consistent and can be used to develop technical specifications. The technological improvement, quality commitment, standardization, and training, reduce TE. An update of TE every five years is therefore recommended. TE assessment in lymphocyte subsets is a helpful and reliable tool to improve laboratory performance and data-based decision-making trust.
Acknowledgments
The authors want to acknowledge the Spanish Society for Immunology and the Iberian Society of Cytometry for their kind allowance to use EPT data, to every lab that took the interlaboratory comparisons over these 10 years for their contribution, and to all anonymous blood donors that consented to the use of their biological samples, as well as the Biobanco del Centro de Hemoterapia y Hemodonación de Castilla y León, that supplies the samples to the GECLID program.
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Research ethics: The local Institutional Review Board deemed the study exempt from review.
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Informed consent: Informed consent was obtained from all individuals included in this study.
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Data availability: The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request
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Author contributions: D.S.S., M.C.M.A.: contributed to the design of the project. D.S.S., F.P.P.: performed the analytic calculations, implementation of the computer code, and supporting algorithms. D.S.S., A.C.B.: analysis of the results and writing the manuscript. J.I.V., M.L.H.: critical review, commentary, and revision. L.B.P., M.C.M.A.: Provision of study materials. All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: M. Carmen Martín is the GECLID program Manager. All other authors state no conflict of interest.
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Research funding: None declared.
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Supplementary Material
This article contains supplementary material (https://doi.org/10.1515/cclm-2023-0470).
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