Bostick W D, Mrochek J E
Clin Chem. 1977 Sep;23(9):1633-9.
The differential activation method for the determination of the "myocardial" isoenzyme of creatine kinase (MB) is based on the computed difference in activity of serum aliquots activated by the combination of dithiothreitol and glutathione (skeletal plus myocardial creatine kinase) and by glutathione alone (skeletal creatine kinase). The unique ability of the Centrifugal Fast Analyzer to perform analyses in parallel is used to precisely measure (CV = 0.1-1.5%) the activity of the two chemically activated aliquots. Statistical considerations concerning the reliability of this difference estimation are discussed with respect to both the precision of the rate measurements and to the relative amount of isoenzyme MB present. Another potential source of error in the analysis of the two differently activated aliquots, namely variation in lag phases, is circumvented by use of a linear-search FOCAL software package. This program searches the data for a linear segment of maximum slope, automatically rejecting those data that appear in lag or depletion regions of the curve representing the progress of the reaction. Correspondence of the results obtained with those of comparison techniques (chromatography and electrophoresis) are discussed.
用于测定肌酸激酶（MB）“心肌”同工酶的差异激活法基于计算由二硫苏糖醇和谷胱甘肽组合激活的血清等分试样（骨骼肌加心肌肌酸激酶）与仅由谷胱甘肽激活的血清等分试样（骨骼肌肌酸激酶）的活性差异。离心快速分析仪并行进行分析的独特能力用于精确测量（CV = 0.1 - 1.5%）两种化学激活的等分试样的活性。关于这种差异估计的可靠性的统计考虑因素在速率测量的精度和存在的同工酶MB的相对量方面都进行了讨论。在分析两种不同激活的等分试样时，另一个潜在的误差来源，即滞后阶段的变化，通过使用线性搜索FOCAL软件包得以规避。该程序在数据中搜索最大斜率的线性段，自动排除那些出现在代表反应进程的曲线的滞后或耗尽区域中的数据。讨论了所获得的结果与比较技术（色谱法和电泳法）的结果的一致性。
