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Abstract：
BACKGROUND: Inherited antithrombin, protein C, and protein S deficiency increase the risk of venous thromboembolism. The presence of defects can be identified by clinical laboratory assays. In most Chinese clinical laboratories, the screening tests for antithrombin, protein C, and protein S deficiency are their activity assays. Ensuring appropriate pre-analytical storage conditions for activity tests is essential. This study aimed to assess the effects of storage conditions on antithrombin, protein C, and protein S activity in frozen plasma.
METHODS: We collected the remaining plasma of 29 patients. The baseline of antithrombin, protein C, and protein S activity values were tested within 4 h. Then, each sample was sub-packaged into 4 EP tubes, and was stored at -20 °C for 3 days, -20 °C for 7 days, -80 °C for 3 days, and - 80 °C for 7 days, respectively. After thawing, samples were tested by two systems.
RESULTS: The percentage deviation of antithrombin and protein C activity assay was<10% compared with the initial values. Protein S activity showed a significant reduction in frozen plasma, with a deviation > 10%. Some samples, initially within the normal range, were classified as abnormal after freezing storage.
CONCLUSIONS: Our study indicated that antithrombin and protein C remain stable when stored at -20 °C or -80 °C in a week. We argued that Protein S activity is not stable in frozen plasma. The use of frozen-thawed plasma for PS activity assay may result in overdiagnosis of protein S deficiency.
METHODS: We collected the remaining plasma of 29 patients. The baseline of antithrombin, protein C, and protein S activity values were tested within 4 h. Then, each sample was sub-packaged into 4 EP tubes, and was stored at -20 °C for 3 days, -20 °C for 7 days, -80 °C for 3 days, and - 80 °C for 7 days, respectively. After thawing, samples were tested by two systems.
RESULTS: The percentage deviation of antithrombin and protein C activity assay was<10% compared with the initial values. Protein S activity showed a significant reduction in frozen plasma, with a deviation > 10%. Some samples, initially within the normal range, were classified as abnormal after freezing storage.
CONCLUSIONS: Our study indicated that antithrombin and protein C remain stable when stored at -20 °C or -80 °C in a week. We argued that Protein S activity is not stable in frozen plasma. The use of frozen-thawed plasma for PS activity assay may result in overdiagnosis of protein S deficiency.
摘要：
背景：遗传性抗凝血酶，蛋白C,蛋白S缺乏会增加静脉血栓栓塞的风险。缺陷的存在可以通过临床实验室测定来鉴定。在大多数中国临床实验室，抗凝血酶的筛选试验,蛋白C,和蛋白S缺乏是他们的活性测定。确保活动测试的适当分析前储存条件至关重要。本研究旨在评估储存条件对抗凝血酶的影响，蛋白C,和冷冻血浆中的蛋白S活性。
方法：我们收集了29名患者的剩余血浆。抗凝血酶的基线，蛋白C,和蛋白质S活性值在4小时内进行测试。然后，每个样品被分装到4个EP管中，并在-20°C下储存3天，-20°C持续7天,-80°C持续3天，和-80°C持续7天，分别。解冻后,样品通过两个系统进行测试。
结果：与初始值相比，抗凝血酶和蛋白C活性测定的百分比偏差<10％。蛋白S活性在冷冻血浆中显示显著降低,偏差>10%。一些样品，最初在正常范围内，在冷冻储存后被归类为异常。
结论：我们的研究表明，抗凝血酶和蛋白C在-20°C或-80°C下储存一周时保持稳定。我们认为蛋白S活性在冷冻血浆中不稳定。使用冻融血浆进行PS活性测定可能会导致蛋白S缺乏症的过度诊断。
方法：我们收集了29名患者的剩余血浆。抗凝血酶的基线，蛋白C,和蛋白质S活性值在4小时内进行测试。然后，每个样品被分装到4个EP管中，并在-20°C下储存3天，-20°C持续7天,-80°C持续3天，和-80°C持续7天，分别。解冻后,样品通过两个系统进行测试。
结果：与初始值相比，抗凝血酶和蛋白C活性测定的百分比偏差<10％。蛋白S活性在冷冻血浆中显示显著降低,偏差>10%。一些样品，最初在正常范围内，在冷冻储存后被归类为异常。
结论：我们的研究表明，抗凝血酶和蛋白C在-20°C或-80°C下储存一周时保持稳定。我们认为蛋白S活性在冷冻血浆中不稳定。使用冻融血浆进行PS活性测定可能会导致蛋白S缺乏症的过度诊断。
