Institute of Hematology and Blood Transfusion, National Reference Laboratory for Disorders in Hemostasis.
Charles University, First Faculty of Medicine, Prague, Czech Republic.
Blood Coagul Fibrinolysis. 2023 Sep 1;34(6):377-384. doi: 10.1097/MBC.0000000000001239. Epub 2023 Jul 19.
Degradation of coagulation proteins in frozen plasma may influence assay results. The aims of this study were to explore the changes in coagulation parameters in patient plasma and internal quality control (IQC) after different freezing and storage conditions during the short-term and long-term periods.
Platelet poor plasma was prepared from citrated peripheral blood collected from a group of healthy donors. The plasma was pooled, frozen and stored in a variety of freezing and storage conditions. The changes were monitored using routine coagulation assays, as well as factor VIII (FVIII) and protein S (PS) assays.
Plasma stored in liquid nitrogen (LN 2 ) or in -80°C showed long-term stable values for routine tests for a period of over 12 months, and 6 months for FVIII. Interestingly, the activated partial thromboplastin time (aPTT) showed a temporary significant prolongation over the first two weeks. Plasma frozen and stored in -40°C is not viable for aPTT and FVIII testing, otherwise it can be used for other parameters for up to 4 months. PS showed a significant increase in all frozen samples. Freezing rate has a significant impact on plasma quality and the final storage temperature influences the long-term stability.
The optimal storage conditions are ultra-low temperatures (LN 2 or -80°C) and the highest freezing rate possible. However, frozen plasma is not viable for IQC of aPTT during a period of two weeks after freezing. This study is unique in its conception as a practical guide for the handling of frozen plasma samples in modern laboratory settings.
冷冻血浆中凝血蛋白的降解可能会影响检测结果。本研究旨在探讨在短期和长期内，不同冷冻和储存条件下患者血浆和内部质量控制（IQC）凝血参数的变化。
从一组健康供体采集柠檬酸盐外周血制备血小板缺乏血浆。将血浆汇集、冷冻并在各种冷冻和储存条件下储存。使用常规凝血检测以及因子 VIII（FVIII）和蛋白 S（PS）检测监测变化。
储存在液氮（LN 2）或-80°C 的血浆在超过 12 个月的时间内对常规测试具有长期稳定的值，FVIII 的值为 6 个月。有趣的是，激活部分凝血活酶时间（aPTT）在前两周内暂时显著延长。储存在-40°C 的血浆不适合用于 aPTT 和 FVIII 测试，但可以在长达 4 个月的时间内用于其他参数。PS 在所有冷冻样本中均显著增加。冷冻速率对血浆质量有重大影响，最终储存温度影响长期稳定性。
最佳储存条件为超低温（LN 2 或-80°C）和尽可能高的冷冻速率。然而，在冷冻后两周内，冷冻血浆不适合用于 aPTT 的 IQC。本研究在概念上是独特的，它为现代实验室环境中冷冻血浆样本的处理提供了实用指南。
