Leroux M L, Rabson J, Desjardins P R
Clin Chem. 1984 Sep;30(9):1552-4.
We evaluated the clinical effectiveness of measuring creatine kinase (CK; EC 2.7.3.2) isoenzyme MB and lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes in diagnosis of acute myocardial infarction. We used an agarose electrophoresis method to measure CK and LD isoenzymes and the Du Pont aca column method to measure CK-MB. Serial blood specimens were drawn from 100 patients consecutively admitted to our Coronary Care Unit. Because of the low diagnostic specificity for CK-MB measurements by both agarose electrophoresis and the discrete-analysis method, as compared with reported values, we re-evaluated our isoenzyme data by using Receiver Operating Characteristic curves. Such analysis of the data established optimal decision levels of greater than or equal to 25 U/L and greater than or equal to 18 U/L plus greater than or equal to 6% of total CK for serum CK-MB measured by the agarose electrophoresis and the aca methods, respectively, and an optimal decision level of greater than or equal to 0.92 for the ratio of LD 1/2 measured after agarose electrophoresis. At these decision levels we obtained a sensitivity of 100%, 100%, and 95% and a specificity of 94%, 92%, and 90% for CK-MB (agarose electrophoresis), CK-MB (aca), and the LD 1/2 ratio, respectively.
我们评估了测量肌酸激酶（CK；EC 2.7.3.2）同工酶MB和乳酸脱氢酶（LD；EC 1.1.1.27）同工酶在急性心肌梗死诊断中的临床有效性。我们采用琼脂糖电泳法测量CK和LD同工酶，采用杜邦aca柱法测量CK-MB。从连续入住我们冠心病监护病房的100例患者中采集系列血标本。与报道值相比，由于琼脂糖电泳法和离散分析法测量CK-MB的诊断特异性较低，我们使用受试者工作特征曲线重新评估了同工酶数据。对数据的此类分析分别确定了琼脂糖电泳法和aca法测量血清CK-MB时的最佳判定水平，分别为大于或等于25 U/L以及大于或等于18 U/L加上总CK的大于或等于6%，琼脂糖电泳后测量的LD 1/2比值的最佳判定水平为大于或等于0.92。在这些判定水平下，CK-MB（琼脂糖电泳法）、CK-MB（aca法）和LD 1/2比值的敏感性分别为100%、100%和95%，特异性分别为94%、92%和90%。
