Effect of freezing method and storage at-20 °C and-70 °C on prothrombin time, aPTT and plasma fibrinogen levels
Effect of freezing method and storage at-20 °C and-70 °C on prothrombin time, aPTT and plasma fibrinogen levels
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DOI：
10.1016/j.thromres.2008.11.010
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发表时间：
2009-05-01
影响因子：
7.5
通讯作者：
Dempfle, Carl-Erik
中科院分区：
文献类型：
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作者：
Alesci, Sonja;Borggrefe, Martin;Dempfle, Carl-Erik
临床和流行病学试验通常涉及凝血试验（包括纤维蛋白原）的中心实验室分析，这需要冷冻血浆样本。尽管推荐通过将样品管浸入液氮中快速冷冻并在-70 ° C下储存，但血浆样品通常直接转移到储存室中，并在-20 ° C下储存。使用动力学纤维蛋白原测定的凝血酶原时间（PT）、活化部分凝血活酶时间（aPTT）和纤维蛋白原、PT衍生的纤维蛋白原，和免疫测定法在来自16名健康献血者的新鲜血浆样品中进行测量。此外，制备了4组等分试样。将组A直接转移到-20 ℃的储存室中，组B首先在液氮中速冻，然后转移到-20 ℃的室中。将组C直接转移到-70 ℃冷冻机中，组D首先在液氮中速冻，然后储存在-70 ℃下。在储存1、2、3和4个月后解冻等分试样并重复实验室测定。PT和aPTT受冷冻和储存的强烈影响。相反，冷冻对纤维蛋白原水平几乎没有影响。所有变体的差异均低于3%。与-20 ° C相比，在-70 ° C下储存的样品的变化较小，并且与未速冻的样品相比，速冻的样品的变化较小。与新鲜样本相比，冷冻和解冻样本产生的纤维蛋白原水平略高。凝血酶原时间和aPTT应在新鲜样本中测量，因为冷冻对结果有不稳定和不可预测的影响。相比之下，冷冻和储存对纤维蛋白原测定结果的影响很小。本研究的局限性在于仅使用了来自健康献血员的样本。具有异常纤维蛋白原浓度或具有异常凝血因子浓度的血浆样品可能表现不同。(C)2008爱思唯尔有限公司保留所有权利。
Clinical and epidemiological trials often involve central laboratory analyses of coagulation tests, including fibrinogen, which requires freezing of the plasma samples. Although rapid freezing by immersion of sample tubes in liquid nitrogen and storage at -70 degrees C is recommended, plasma samples are often transferred directly to the storage compartments, and stored at -20 degrees C.Prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen using a kinetic fibrinogen assay, PT-derived fibrinogen, and an immunoassay were measured in fresh plasma samples from 16 healthy blood donors. In addition, four sets of aliquots were prepared. Set A was transferred directly to a -20 degrees C storage compartment, set B was first snap-frozen in liquid nitrogen and then transferred to the -20 degrees C compartment. Set C was transferred directly to a -70 degrees C freezer, set D was first snap-frozen in liquid nitrogen and then stored at -70 degrees C. Aliquots were thawed after one, two, three and four months storage and laboratory assays repeated.PT and aPTT were strongly influenced by freezing and storage. In contrast, freezing had little effect on fibrinogen levels. Differences were below three percent for all variants. Changes were smaller for samples stored at -70 degrees C compared to -20 degrees C, and for snap-frozen compared to not snap-frozen samples. Frozen and thawed samples generated slightly higher fibrinogen levels compared to fresh samples.Prothrombin time and aPTT should be measured in fresh samples, since freezing has an inconstant and unpredictable effect on the results. In contrast, freezing and storage has little effect on results of fibrinogen assays.A limitation of the study is that only samples from healthy blood donors were used. Plasma samples with abnormal fibrinogen concentration, or with abnormal concentrations of coagulation factors might behave differently. (C) 2008 Elsevier Ltd. All rights reserved.