Rothwell D J, Jendrzejczak B, Becker M, Doumas B T
Clin Chem. 1976 Jul;22(7):1024-6.
We investigated lactate dehydrogenase activity in serum and plasma because of the conflicting data found in the literature. We assayed serum, platelet-rich, and platelet-poor plasma by two colorimetric endpoint methods and by an ultraviolet kinetic procedure. Platelet-poor plasma and serum had essentially the same activities by all three methods, whereas the activity in platelet-rich plasma plasma averaged fourfold that in platelet-poor plasma or serum when the assay was performed under conditions that result in lysis of platelets and release of their lactate dehydrogenase. When measurements were performed in platelet-rich plasma under conditions that prevented lysis of platelets, all three types of specimens gave the same results. This occurred when the osmolality of the reaction mixture was about 240 mOsm/kg of water. At an osmolality of about 120 mOsm, the activity of platelet-rich plasma was substantially lower than that of platelet-poor plasma or serum. If plasma must be used, the sample must first be centrifuged (3000 X g, 15 min) to provide a platelet-free plasma.
由于文献中发现的数据相互矛盾，我们对血清和血浆中的乳酸脱氢酶活性进行了研究。我们采用两种比色终点法和一种紫外动力学方法对血清、富血小板血浆和贫血小板血浆进行了测定。在导致血小板裂解并释放其乳酸脱氢酶的条件下进行检测时，贫血小板血浆和血清通过所有三种方法测得的活性基本相同，而富血小板血浆中的活性平均为贫血小板血浆或血清中的四倍。当在防止血小板裂解的条件下对富血小板血浆进行测量时，所有三种类型的标本结果相同。当反应混合物的渗透压约为240 mOsm/kg水时会出现这种情况。在渗透压约为120 mOsm时，富血小板血浆的活性明显低于贫血小板血浆或血清。如果必须使用血浆，则必须首先将样品离心（3000×g，15分钟）以提供无血小板血浆。
