两种检测系统测定血清半胱氨酸蛋白酶抑制剂C的偏差评估

Evaluation on the bias of two detection systems for serum cystatin C

目的对液相透射比浊检测系统和颗粒增强散射比浊检测系统测定半胱氨酸蛋白酶抑制剂C(CysC)结果偏差进行方法学比较及偏差评估。方法按照美国临床实验室标准化委员会(NCCLS)EP9-A2文件,以40例血清标本分别在罗氏MODULAR P800全自动生化分析仪和西门子BN-II特定蛋白分析仪上进行双份重复测定。将测定数据结果进行离群点检查,线性回归分析,计算预期偏差及可信区间(CI)。结果 2种检测系统Cys C测定结果的相关回归方程为Y=1.216X-0.139,r2=0.978。浓度为0.53、0.95 mg/L时,允许误差在预期偏差95%CI范围内;Cys C浓度为7.85 mg/L时,允许误差<预期偏差95%CI下限。结论 2种检测系统的测定结果呈线性相关。在低浓度时,预计偏差可以接受。在高浓度时,测定结果不一致,预期偏差不可以接受。

Objective To compare methodologically and evaluate the bias of turbidimetric assay and particle- enhanced nephelometric assay for serum cystatin C （Cys C ）. Methods According to the National Committee for Clinical Laboratory Standards （NCCLS） EPg-A2 document, 40 serum samples were determined in duplicate measurement by Roche MODULAR PS00 automatic biochemical analyzer and Siemens BN-Ⅱ specific protein analyzer, respectively. The data were used to check outliers, linear regression was analyzed, and the predictive bias and confidence interval（CI） were calculated. Results The linear regression equation was Y = 1. 216X -0. 139 ,r2 = 0. 978. When the Cys C concentrations were 0.53 mg/L and 0.95 mg/L, the acceptable biases were in the range of 95% CI of predictive bias. However, when the Cys C concentration was 7.85 mg/L, the acceptable bias was 〈 the low limit of 95% CI of predictive bias. Conclusions The results of the 2 detection systems have linear correlation. The predictive bias of measured results between the 2 detection systems is acceptable except the high concentration.