Williams K M, Williams A E, Kline L M, Dodd R Y
Transfusion. 1987 Sep-Oct;27(5):431-3. doi: 10.1046/j.1537-2995.1987.27587320539.x.
In this study the authors examine the effects of common storage and handling procedures on serum alanine aminotransferase (ALT) levels. Clotted blood samples from 14 subjects were centrifuged at 280 X g for 10 minutes. Serum was tested immediately for baseline ALT levels and aliquots were stored at 22, 4, -20, and -80 degrees C. Additional serums were stored on the clot at 22 and 4 degrees C. ALT quantitation was performed at intervals of 3, 6, 9, and 24 hours and on Days 2, 4, 6, and 8. Unseparated tubes were sampled both proximal and distal to the red cells to determine ALT leakage from red cells lysis. For all storage conditions, gradual loss of activity occurred over time. Mean activity loss in separated serum at 2 days was 6 percent at 4 degrees C and 20 percent at 22 degrees C. Mean loss in unseparated serum was 3 percent at 4 degrees C and 12 percent at 22 degrees C. Marked ALT loss averaging 46 percent by day 6 occurred with storage at -20 degrees C, whereas storage at -80 degrees C resulted in an 8 percent decrease for the same period. For storage of up to 1 week, it is recommended that serum be separated early and retained at 4 degrees C. Frozen samples should be kept at -80 degrees C. Storage of separated or unseparated blood for up to 24 hours at 22 or 4 degrees C, as commonly found in blood centers, will marginally adversely affect the accuracy of ALT determination.
在本研究中，作者检测了常见储存和处理程序对血清丙氨酸氨基转移酶（ALT）水平的影响。采集了14名受试者的凝血样本，以280×g离心10分钟。立即检测血清的基线ALT水平，并将等分试样分别储存在22℃、4℃、-20℃和-80℃。另外的血清样本在凝血状态下分别储存在22℃和4℃。分别在3、6、9和24小时以及第2、4、6和8天进行ALT定量检测。对未分离的试管在红细胞近端和远端取样，以确定红细胞裂解导致的ALT泄漏情况。在所有储存条件下，随着时间的推移，活性逐渐丧失。在4℃下储存2天，分离血清中的平均活性损失为6%，在22℃下为20%。未分离血清在4℃下的平均损失为3%，在22℃下为12%。在-20℃下储存，到第6天ALT平均损失达46%，而在-80℃下储存同期则下降了8%。对于长达1周的储存，建议尽早分离血清并保存在4℃。冷冻样本应保存在-80℃。如血液中心常见的那样，在22℃或4℃下将分离或未分离的血液储存长达24小时，会对ALT测定的准确性产生轻微的不利影响。
