Homburger H A, Jacob G L
Clin Chem. 1980 Jun;26(7):861-6.
We compared, in 116 patients, the relative usefulness of results of tests for creatine kinase B isoenzymes, as measured by radioimmunoassay, and the MB isoenzyme, as measured by electrophoresis, in diagnosis of acute myocardial infarction. The radioimmunoassay was specific for isoenzymes of creatine kinase containing the B subunit. All patients with acute transmural infarcts had positive test results by both techniques, but concentrations of B-isoenzymes were more frequently above normal than were MB bands in the case of patients with acute subendocardial infarcts and in the case of all patients with acute myocardial infarcts from whom sera were collected more than 24 h after onset of chest pain. Concentrations of B-isoenzymes also were increased, even when MB bands were not electrophoretically detectable, in specimens from several patients without documented actue myocardial infarcts. These abnormal results presumably were caused by increased concentrations of the BB isoenzyme in serum. Accordingly, an increased concentration of B-isoenzymes had less diagnostic specificity and predictive value for acute myocardial infarction than did a detectable MB band. Results of isoenzyme electrophoresis were more reliable for establishing this diagnosis, but the results of radioimmunoassay were more reliable for excluding it in patients with chest pain as the primary symptom.
我们对116例患者进行了研究，比较了通过放射免疫测定法检测的肌酸激酶B同工酶结果与通过电泳检测的MB同工酶结果在急性心肌梗死诊断中的相对效用。放射免疫测定法对含有B亚基的肌酸激酶同工酶具有特异性。所有急性透壁性梗死患者两种技术的检测结果均为阳性，但对于急性心内膜下梗死患者以及胸痛发作24小时后采集血清的所有急性心肌梗死患者，B同工酶浓度高于正常的情况比MB条带更为常见。在一些无急性心肌梗死记录的患者标本中，即使电泳检测不到MB条带，B同工酶浓度也会升高。这些异常结果可能是由血清中BB同工酶浓度升高所致。因此，与可检测到的MB条带相比，B同工酶浓度升高对急性心肌梗死的诊断特异性和预测价值较低。同工酶电泳结果对于确立该诊断更为可靠，但放射免疫测定结果对于以胸痛为主要症状的患者排除急性心肌梗死更为可靠。
