The most common applications of flow cytometry (FC) include diagnostics of haemato-oncological disorders, based on analysis of bone marrow, peripheral blood (PB), or cerebrospinal fluid (CSF) samples. A proper diagnostic process requires standardisation in setting the optimal time frame between material collection and the assay. Unfortunately, this might be difficult to achieve in daily practice due to unintended shipment delays, which might compromise large-scale multicentre studies. Thus, material fixation should be considered as a solution. The most widely used fixative agents are: paraformaldehyde, TransFix®, Cyto-Chex®, and serum-containing media. In this review, we attempted to summarise the literature data on the influence of sample storage under different temperatures and times combined with different fixation conditions on the cell count and marker expression levels. Based on the findings of several extensive studies employing fixed PB samples, it can be concluded that the performance of particular fixative greatly depends on the analysed marker and specific PB cell population expressing a given antigen. Preservation of absolute cell count was usually better in Cyto-Chex®-fixed PB samples, whereas TransFix® tended to better stabilise marker expression levels. CSF-based studies reveal that both serum-containing media and TransFix® can prevent cellular loss and enhance FC-based detection of leptomeningeal localisations of haematological malignancies, the latter being more available and having longer shelf-life. As both cell count and marker expression level are the main determinants

of quality of biological samples dedicated to FC analyses, it remains to be addressed by the investigators which is the fixative of choice for their specific research aims.

中文翻译：

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流式细胞术分析中生物样品固定对细胞计数和标志物表达稳定性的影响

流式细胞术（FC）的最常见应用包括根据骨髓，外周血（PB）或脑脊髓液（CSF）样品的分析诊断血液肿瘤疾病。正确的诊断过程需要在设置材料收集和测定之间的最佳时间范围内进行标准化。不幸的是，由于意外的运输延迟，这在日常实践中可能难以实现，这可能会损害大规模的多中心研究。因此，材料固定应被视为解决方案。使用最广泛的固定剂是：多聚甲醛，TransFix®，Cyto-Chex®和含血清的培养基。在这篇评论中 我们试图总结有关在不同温度和时间下，不同固定条件下样品存储对细胞计数和标志物表达水平的影响的文献数据。根据使用固定PB样品进行的数项广泛研究的发现，可以得出结论，特定固定剂的性能在很大程度上取决于所分析的标记物和表达给定抗原的特定PB细胞群体。在Cyto-Chex®固定的PB样品中，绝对细胞计数的保存通常更好，而TransFix®倾向于更好地稳定标记物的表达水平。基于CSF的研究表明，含血清的培养基和TransFix®均可防止细胞丢失并增强基于FC的血液系统恶性肿瘤的小脑膜定位的检测，后者的可用性更高，并且货架期更长。由于细胞计数和标志物表达水平都是主要决定因素

专用于FC分析的生物样品的质量，研究者仍有待解决，这是其特定研究目标的固定选择。