Objective: To investigate the analytical performance verification protocols and performance specifications of platelet-dependent von Willebrand factor (VWF) activity testing (VWF:GPIbM) for clinical laboratories. Methods: According to Clinical Laboratory Standards Institute (CLSI) documents and National Health Standard of China, the performance verification of VWF:GPIbM was designed and implemented using Sysmex CS-5100 instrument and its corresponding reagents. (1) Precision verification: Two commercial quality control samples (with normal and low activity levels) and three plasma pools (with activity range from 5.0% to 150.0%) were prepared. Each sample was tested five times daily for five consecutive days. The coefficient of variation (CV) of intra-and inter-run precisions were calculated, and the precision evaluation criterion was set according to package inserts. (2) Trueness verification: The calibrator was diluted to five reference materials with activity values of 5.2%, 31.2%, 62.4%, 104.0% and 138.7%, and each reference material was tested five times daily for five consecutive days. The bias between the measured value and the reference value was calculated, and the trueness evaluation criterion was set according to the total allowable error. (3) Linearity verification: Ten pooled plasmas with theoretical value range from 3.6% to 160.4% were prepared for the linearity verification of two calibration curves set by the manufacturer (i.e. low range and normal range calibration curve). Each pooled plasma was tested three times in a single run. The slope and R2 of linear regression of mean of measured value and theoretical value, as well as bias, were calculated, and the linearity evaluation criterion was set according to National Health Standard of China and package inserts. (4) Limit of quantitation verification: The calibrator was diluted to two reference materials with activity values of 3.3% and 2.7%, and each material was tested twelve times. The limit of quantitation evaluation criterion was set according to CLSI document. Results: The CVs of intra-and inter-run were 1.0%-2.5% and 1.1%-2.6%, respectively. The biases of trueness verification were -0.4%, 1.0%, -2.6%, 0.3% and -2.7%, respectively. The linearity verification results of low range (3.6%-31.8%) and normal range (28.4%-160.4%) showed that the slopes of regression equation were 1.021 7 and 0.996 2, respectively, R2 were 0.993 5 and 0.993 9, respectively, and the biases with 0-1.8% and -10.1%-0 of plasmas met the criterion. The biases ranged from -0.4% to 0.3% of test results in the verification of limit of quantitation met the criterion. Conclusion: The verification results of VWF:GPIbM assay for precision, trueness, linearity and limit of quantification meet the performance requirements indicated in the package inserts and the criteria set in this study, which can be taken as a reference of performance verification for the clinical laboratories.
目的： 探讨适合临床实验室使用的血管性血友病因子（VWF）与血小板结合活性（VWF：GPIbM）检测的性能验证方法和指标。 方法： 参考美国临床和实验室标准协会（CLSI）系列文件和我国卫生行业标准，使用Sysmex CS-5100仪器及配套试剂，设计方案并验证其检测VWF：GPIbM的性能。（1）精密度验证：使用正常值、低值质控品和3种不同活性的混合血浆（活性范围为5.0%~150.0%），每天重复检测各样品5次，连续5 d，计算批内和批间变异系数（CV），依据产品说明书标示的性能要求设定精密度评价标准；（2）正确度验证：将配套校准物稀释成活性参考值分别为5.2%、31.2%、62.4%、104.0%和138.7%的样品，各样品重复检测次数与精密度实验相同，计算检测均值与参考值的偏倚，依据允许总误差设定正确度评价标准；（3）线性验证：配制10种不同活性的混合血浆（活性理论值范围为3.6%~160.4%），用于低活性水平和正常活性水平校准曲线的线性验证，重复检测各样品3次，计算检测均值和理论值的线性回归方程的斜率、R2以及偏差，依据行业标准和产品说明书的要求设定线性评价标准；（4）定量限验证：将配套校准物稀释成活性为3.3%和2.7%的样品，重复检测各样品12次，依据CLSI文件设定评价标准。 结果： 精密度验证的批内和批间CV分别为1.0%~2.5%和1.1%~2.6%；正确度验证结果的偏倚分别为-0.4%、1.0%、-2.6%、0.3%和-2.7%；低活性水平（3.6%~31.8%）和正常活性水平（28.4%~160.4%）线性验证结果显示，回归方程的斜率分别为1.021 7和0.996 2，R2分别为0.993 5和0.993 9，各样品检测结果的偏差为0~1.8%、-10.1%~0，均符合要求；定量限验证检测结果的偏差为-0.4%~0.3%，均符合要求。 结论： VWF：GPIbM方法的精密度、正确度、线性和定量限验证结果均满足产品说明书标示的性能要求或本研究设定的评价标准，可为临床实验室的性能验证提供参考。.