BACKGROUND As part of quality assurance in laboratories (labs) offering clinical cell analysis by flow cytometry (FCM), cell counting precision and robustness are evaluated but international desirable ranges are still missing. The aim of this study was to provide desirable interlaboratory variability reference values. METHODS A prospective survey on monthly quality assessment was proposed to all French laboratories routinely performing lymphocyte subpopulation quantification, over one arbitrarily selected month (June 2017), regardless of instrument, counting system and quality controls used. Relative variabilities of the commercially available internal quality control (IQC) used locally were collected. Robust mean, standard deviation and CV were calculated on relative and absolute counts. RESULTS Sixty-two labs participated, providing 91 sets of data on 82 instruments. All but three were enrolled in external quality assessment (EQA) and 46 in externalized IQA. The mean CV of five repeats ranged from 1.00 ± 0.33 for T cells to 4.78 ± 1.92 for NK cells and from 2.88 ± 1.46 to 5.87 ± 1.83 for relative and absolute counts, respectively. The precision correlated directly to the concentration of cells rather than the phenotype. Negligible differences were observed between IQC material: Multicheck™ (3.36 ± 1.30, n = 11); Immunotrol™ (3.62 ± 3.24, n = 21) and Statusflow™ (3.63 ± 1.87, n = 24) on CD4+ T cell, for example. Little difference was observed between counting systems such as Flowcount™ (4.55 ± 3.45, n = 19), Trucount™ (3.17 ± 1.40, n = 30) and the fully automated Aquios™ system (1.87 ± 0.75, n = 5) on single platforms, while dual platform CV was at 2.00 ± 0.58 (n = 2) on CD4+ T cell, as example. Robustness was measured on 21 ± 11 consecutive analyses of the same IQC material, providing CVs ranging from 4.45 ± 1.74 for T cells to 7.57 ± 2.19 for NK absolute counts. Average residuals calculated from the different low count IQC samples for CD4 T cells (median value below 200 cells/μl) were below 10 cells/μl, demonstrating their robustness for medical decisions. CONCLUSIONS Real life variabilities in cell counting are directly related to the cell concentration and not to their phenotype. Desirable ranges within three SD are proposed according to different cell levels, based on 62 labs, different IQC material and systems. © 2018 International Clinical Cytometry Society.

中文翻译：

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流式细胞术对淋巴细胞计数的可接受的“现实生活”变异性。

背景技术作为通过流式细胞术（FCM）提供临床细胞分析的实验室（实验室）质量保证的一部分，评估了细胞计数的准确性和鲁棒性，但仍缺少国际上理想的范围。这项研究的目的是提供理想的实验室间变异性参考值。方法向所有法国实验室进行了每月质量评估的前瞻性调查，该实验室在任意选定的一个月（2017年6月）中常规进行淋巴细胞亚群定量分析，无论使用何种仪器，计数系统和质量控制手段。收集当地使用的市售内部质量控制（IQC）的相对变异性。根据相对和绝对值计算稳健的均值，标准差和CV。结果有62个实验室参加，提供82项仪器的91组数据。除三人外，其余所有人均参加了外部质量评估（EQA），46人参加了外部化IQA。五个重复的平均CV范围从T细胞的1.00±0.33到NK细胞的4.78±1.92，相对和绝对计数的范围分别从2.88±1.46到5.87±1.83。精度与细胞浓度而不是表型直接相关。IQC材料之间的差异可忽略不计：Multicheck™（3.36±1.30，n = 11）；例如，在CD4 + T细胞上的Immunotrol™（3.62±3.24，n = 21）和Statusflow™（3.63±1.87，n = 24）。在单个计数系统上，例如Flowcount™（4.55±3.45，n = 19），Trucount™（3.17±1.40，n = 30）和全自动Aquios™系统（1.87±0.75，n = 5），观察到的差异很小。平台，而双平台CV为2.00±0。例如，在CD4 + T细胞上为58（n = 2）。在同一IQC材料的21±11次连续分析中测量了稳健性，CV范围从T细胞的4.45±1.74到NK绝对计数的7.57±2.19。根据CD4 T细胞的不同低计数IQC样本（中值低于200细胞/μl）计算出的平均残差低于10细胞/μl，证明了其在医学决策上的稳健性。结论细胞计数中的现实生活变异与细胞浓度直接相关，而与它们的表型无关。根据62个实验室，不同的IQC材料和系统，根据不同的细胞水平，提出了三个SD的理想范围。©2018国际临床细胞计量学会。提供的CV从T细胞的4.45±1.74到NK绝对计数的7.57±2.19不等。根据CD4 T细胞的不同低计数IQC样本（中值低于200细胞/μl）计算出的平均残差低于10细胞/μl，证明了其在医学决策上的稳健性。结论细胞计数中的现实生活变异与细胞浓度直接相关，而与它们的表型无关。根据62个实验室，不同的IQC材料和系统，根据不同的细胞水平，建议在三个SD内的理想范围。©2018国际临床细胞计量学会。提供的CV范围从T细胞的4.45±1.74到NK绝对计数的7.57±2.19。根据CD4 T细胞的不同低计数IQC样本（中值低于200细胞/μl）计算出的平均残差低于10细胞/μl，证明了其在医学决策上的稳健性。结论细胞计数中的现实生活变异与细胞浓度直接相关，而与它们的表型无关。根据62个实验室，不同的IQC材料和系统，根据不同的细胞水平，建议在三个SD内的理想范围。©2018国际临床细胞计量学会。展示了它们在医疗决策中的强大能力。结论细胞计数中的现实生活变异与细胞浓度直接相关，而与它们的表型无关。根据62个实验室，不同的IQC材料和系统，根据不同的细胞水平，建议在三个SD内的理想范围。©2018国际临床细胞计量学会。展示了它们在医疗决策中的强大能力。结论细胞计数中的现实生活变异与细胞浓度直接相关，而与它们的表型无关。根据62个实验室，不同的IQC材料和系统，根据不同的细胞水平，建议在三个SD内的理想范围。©2018国际临床细胞计量学会。