Abstract：
OBJECTIVE: M-protein quantification by peak integration in serum protein electrophoresis (SPE) plays a central role in diagnosing, prognosing and monitoring monoclonal gammopathies. The conventional perpendicular drop (PD) integration approach integrates M-spikes from the baseline, which performs acceptably when the M-protein concentration is relatively high compared to the amount of background proteins present. The alternative peak-integration protocol by tangential skim (TS), however, allows for more accurate M-protein estimations by excluding background proteins. Despite some guideline recommendations, TS has been poorly adopted, making an understanding of the differences between the two protocols and their potential impacts paramount when considering a change from PD to TS.
METHODS: We conducted retrospective investigations of the differences in M-protein quantification over large concentration ranges between PD and TS on 3 of the most popular electrophoresis platforms.
RESULTS: Compared to PD, TS gave consistently lower results; the differences between the two methods increased tremendously and became more sporadic as M-protein concentrations dropped below 15 g/L in all 3 platforms. At < 15 g/L, the average % difference ranged from -81 % to -95 %, while above 15 g/L, the average % difference was only -13 to -31 %. Medical decision point analyses using linear regression predicted statistically significant and platform-dependent differences, which could impact clinical interpretation.
CONCLUSIONS: Careful consideration of the magnitude of concentration changes and the potential impacts on patient classification and management should be made when switching to TS for M-protein quantification.
METHODS: We conducted retrospective investigations of the differences in M-protein quantification over large concentration ranges between PD and TS on 3 of the most popular electrophoresis platforms.
RESULTS: Compared to PD, TS gave consistently lower results; the differences between the two methods increased tremendously and became more sporadic as M-protein concentrations dropped below 15 g/L in all 3 platforms. At < 15 g/L, the average % difference ranged from -81 % to -95 %, while above 15 g/L, the average % difference was only -13 to -31 %. Medical decision point analyses using linear regression predicted statistically significant and platform-dependent differences, which could impact clinical interpretation.
CONCLUSIONS: Careful consideration of the magnitude of concentration changes and the potential impacts on patient classification and management should be made when switching to TS for M-protein quantification.
摘要：
目的：通过血清蛋白电泳（SPE）中的峰积分定量M蛋白在诊断中起着重要作用，预测和监测单克隆丙种球蛋白。传统的垂直液滴(PD)积分方法从基线积分M尖峰，当M蛋白浓度与存在的背景蛋白的量相比相对高时,其表现可接受。通过切向撇渣(TS)的替代峰积分协议，然而,通过排除背景蛋白，可以更准确地估计M蛋白。尽管有一些指导方针建议，TS被采纳得很差，在考虑从PD更改为TS时，了解两个协议之间的差异及其潜在影响至关重要。
方法：我们在3种最流行的电泳平台上，对PD和TS在大浓度范围内的M蛋白定量差异进行了回顾性研究。
结果：与PD相比，TS给出的结果始终较低；两种方法之间的差异大大增加，并且随着所有3个平台中M蛋白浓度降至15g/L以下而变得更加零星。在<15g/L时，平均百分比差异从-81%到-95%，在15g/L以上时，平均%差异仅为-13至-31%。使用线性回归的医疗决策点分析预测了具有统计学意义和平台依赖性的差异，这可能会影响临床解释。
结论：转换为TS进行M蛋白定量时，应仔细考虑浓度变化的幅度以及对患者分类和管理的潜在影响。
方法：我们在3种最流行的电泳平台上，对PD和TS在大浓度范围内的M蛋白定量差异进行了回顾性研究。
结果：与PD相比，TS给出的结果始终较低；两种方法之间的差异大大增加，并且随着所有3个平台中M蛋白浓度降至15g/L以下而变得更加零星。在<15g/L时，平均百分比差异从-81%到-95%，在15g/L以上时，平均%差异仅为-13至-31%。使用线性回归的医疗决策点分析预测了具有统计学意义和平台依赖性的差异，这可能会影响临床解释。
结论：转换为TS进行M蛋白定量时，应仔细考虑浓度变化的幅度以及对患者分类和管理的潜在影响。
