液相色谱串联质谱技术在载脂蛋白E室间质量评价中的应用

Performance of liquid chromatography tandem mass spectrometry in EQA program of apolipoprotein E measurement

目的探讨液相色谱串联质谱技术(LC-MS/MS)在载脂蛋白E(apo E)室间质量评价中的应用。方法分别将5份混合人血清样品冷链运送到76家实验室,用免疫比浊法(ITA)进行单次检测。以同位素标记精氨酸的肽段为内标,对标本进行变性、烷基化和胰蛋白酶酶解处理,液相色谱部分采用SB-C18色谱柱分离,质谱部分采用正离子模式和多反应监测定量。JMP13.0软件分析不同方法分组所对应的相对偏倚。结果对于所有样品,ITA检测apo E的方法组内不精密度在1.7%至20.4%之间。总不精密度在8%左右(s B~s E样品)。5个样品相对偏倚的均值分别是(按照样品浓度由低到高排列):-34.2%、-9.4%、-9.8%、-2.7%和-2.1%。高浓度样品比低浓度样品更接近LC-MS/MS检测结果。结论 LC-MS/MS检测apo E可评价免疫法的准确性,为临床应用提供帮助。

Objectives To investigate the application potentiality of liquid chromatography tandem mass spectrometry( LC-MS/MS) on establishing target value of apolipoprotein E( apo E) in external quality assessment scheme. Methods Five pooled human samples were distributed to 76 clinical laboratories by cold-chain for single measurement with immunoturbidimetric assay( ITA). The samples underwent denaturing,alkylation and trypsin digestion with addition of internal standards of isotope labeling arginine. SB-C18 column was used for liquid chromatographic separation,and positive ion mode and multiple reactions monitoring of mass spectrometry were employed for quantification and phenotyping. JMP 13.0 software was used for relative bias analysis among various assay groups. Results For all samples,the impression of apo E levels within assay measured by ITA varied with assay manufacturers,ranging from 1.7% to 20.4%. The assay CVs were around 8%( s B-s E spesimen). The mean relative biases of the 5 pooled samples between the results of ITA and LC-MS/MS were-34.2%,-9.4%,-9.8%,-2.7% and-2.1% in the order from low to high levels of samples. The samples with high concentrations were closer to target values than the samples with low concentrations. Conclusion LC-MS/MS could show the potential on assessing the accuracy of ITA,which may promote its clinical application.