Stemerman D, Papadea C, Martino-Saltzman D, O'Connell A C, Demaline B, Austin G E
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia.
Am J Clin Pathol. 1989 Apr;91(4):435-40. doi: 10.1093/ajcp/91.4.435.
Agarose gel electrophoresis has recently replaced cellulose acetate electrophoresis as the preferred technique for monitoring paraprotein levels in patients with plasma cell dyscrasias. The authors studied the accuracy and precision of this method for paraprotein determination. Twenty-seven serum samples with paraprotein concentrations ranging from 5 to 73 g/L were aliquotted and assayed on 20 separate occasions, and the mean and standard deviation for the paraprotein concentration in each serum was established. Linear regression analysis showed that the standard deviation of paraprotein concentration (SD) increased as a function of paraprotein concentration (PC). For IgG paraproteins, the regression equation was SD = 0.041 (PC) + 1.06; R = 0.942; standard error = 0.32. For non-IgG paraproteins the equation was SD = 0.101 (PC) - 0.04; R = 0.851; standard error = 0.5. The accuracy of paraprotein determinations by the agarose gel electrophoretic technique was assessed by comparison with values obtained with the use of a previously validated enzyme-linked immunosorbent assay (ELISA) method for quantitation of IgG subclasses. Results obtained by the two methods were similar and highly correlated: (concentration by electrophoresis) = 0.921 (concentration by ELISA) + 0.46; R = 0.988; standard error = 0.34. The laser densitometric scanning procedure showed a loss of linearity above 60 g/L, indicating the need to dilute sera with very high paraprotein concentrations in order to obtain accurate results. A table is presented that should help pathologists who interpret such scans to determine whether small changes in paraprotein measurements occurring over time represent true changes in paraprotein concentration or merely reflect the analytic variability inherent in the technique.
琼脂糖凝胶电泳最近已取代醋酸纤维素电泳，成为监测浆细胞发育异常患者副蛋白水平的首选技术。作者研究了该方法测定副蛋白的准确性和精密度。将27份副蛋白浓度在5至73 g/L之间的血清样本进行分装，并在20个不同的时间点进行检测，确定每份血清中副蛋白浓度的平均值和标准差。线性回归分析表明，副蛋白浓度的标准差（SD）随副蛋白浓度（PC）的增加而增加。对于IgG副蛋白，回归方程为SD = 0.041（PC）+ 1.06；R = 0.942；标准误差 = 0.32。对于非IgG副蛋白，方程为SD = 0.101（PC）- 0.04；R = 0.851；标准误差 = 0.5。通过与使用先前验证的酶联免疫吸附测定（ELISA）方法定量IgG亚类所获得的值进行比较，评估了琼脂糖凝胶电泳技术测定副蛋白的准确性。两种方法获得的结果相似且高度相关：（电泳浓度）= 0.921（ELISA浓度）+ 0.46；R = 0.988；标准误差 = 0.34。激光密度扫描程序显示，在60 g/L以上线性关系丧失，这表明需要稀释副蛋白浓度非常高的血清，以获得准确的结果。文中给出了一个表格，应有助于解读此类扫描结果的病理学家确定随着时间推移副蛋白测量值的微小变化是代表副蛋白浓度的真实变化，还是仅仅反映了该技术固有的分析变异性。
