Chuang Chih-Kuang, Wang Tuen-Jen, Yeung Chun-Yan, Hsieh Wen-Shyang, Lin Dar-Shong, Ho Shinn-Chamg, Lin Shuan-Pei
Division of Genetics and Metabolism, Department of Medical Research, Taipei 10449, Taiwan.
Clin Biochem. 2006 Jan;39(1):74-7. doi: 10.1016/j.clinbiochem.2005.10.007. Epub 2005 Nov 23.
To assess the severity of circulatory failure, a pyruvate enzymatic assay was performed on whole blood using lactate dehydrogenase to catalyze the conversion of pyruvate to lactate. We investigated factors related to blood sample collection and preparation that might influence the results, including the timing of blood deproteinization, temperature of sample storage, and hemolysis.
A total of 25 whole blood specimens were collected for this study. Each sample was divided into 2 parts: one stored at room temperature (RT) and another kept on ice. The samples were deproteinizied by using 8% perchloric acid (PCA) at varying times after collection; the first deproteinization was immediately after the blood was drawn (0 h), then at 1 h intervals for 6 h and also in samples kept overnight. The supernatant samples were analyzed soon after deproteinization using a COBAS Centrifugal Analyzer. In another set of samples, the blood was immediately deproteinized, and the supernatants were stored at RT and 4 degrees C and assayed for pyruvate at varying times, as above. Finally, the effect of hemolysis on the blood pyruvate enzymatic assay was also evaluated.
When samples were stored at RT, pyruvate levels remained constant until the third h after deproteinization, when there was an approximately 13.3% increase in pyruvate concentration. When whole blood samples were kept at 4 degrees C before deproteinization, pyruvate levels were significantly reduced over time, ranging from 37.8% to 62.2% (paired t test showed a significant mean difference, P < 0.001). No significant differences in pyruvate concentration were observed in supernatant stored at either RT or 4 degrees C. Hemolysis caused a 33.7% increase in the pyruvate concentration, equivalent to 0.18 mg pyruvate per gram per deciliter of hemoglobin.
For a pyruvate enzymatic assay, keeping a whole blood sample at RT will not cause a significant difference in the pyruvate level as long as the sample is immediately deproteinized. Whole blood samples should not be stored in an ice bath for transport, nor should hemolyzed samples be used for a blood pyruvate enzymatic assay.
为评估循环衰竭的严重程度，使用乳酸脱氢酶催化丙酮酸转化为乳酸，对全血进行丙酮酸酶法测定。我们研究了与血样采集和制备相关的可能影响结果的因素，包括血液去蛋白的时间、样品储存温度和溶血情况。
本研究共采集了25份全血标本。每个样品分为两部分：一部分在室温（RT）下保存，另一部分保存在冰上。在采集后的不同时间使用8%高氯酸（PCA）对样品进行去蛋白处理；第一次去蛋白是在采血后立即进行（0小时），然后每隔1小时进行一次，共进行6小时，并且对过夜保存的样品也进行去蛋白处理。去蛋白后立即使用COBAS离心分析仪对上清液样品进行分析。在另一组样品中，血液立即进行去蛋白处理，上清液分别在室温（RT）和4℃下保存，并在不同时间按照上述方法测定丙酮酸。最后，还评估了溶血对血液丙酮酸酶法测定的影响。
当样品在室温（RT）下保存时，丙酮酸水平在去蛋白后的第3小时之前保持恒定，之后丙酮酸浓度大约增加了13.3%。当全血样品在去蛋白前保存在4℃时，丙酮酸水平随时间显著降低，降低幅度在37.8%至62.2%之间（配对t检验显示平均差异显著，P < 0.001）。在室温（RT）或4℃下保存的上清液中，丙酮酸浓度未观察到显著差异。溶血导致丙酮酸浓度增加33.7%，相当于每克每分升血红蛋白中丙酮酸增加0.18毫克。
对于丙酮酸酶法测定，只要全血样品立即去蛋白，在室温（RT）下保存不会导致丙酮酸水平出现显著差异。全血样品运输时不应保存在冰浴中，溶血样品也不应用于血液丙酮酸酶法测定。
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