目的 对新一代脂蛋白(a)[Lp(a)]颗粒浓度测定方法(方法A)和2种Lp(a)质量浓度测定方法(方法B、方法C)进行性能验证,并评价其临床应用价值.方法 评价3种方法的精密度、线性范围、临床可报告范围及回收率.采用3种方法分别检测322例样本的Lp(a)水平,并进行相关性和分组一致性比较.方法A以75 nmol/L、方法B和方法C以300 mg/L作为Lp(a)的判断限,比较冠状动脉疾病(CAD)组、外周动脉疾病(PAD)组、脑卒中组及正常对照组3种方法检测Lp(a)的阳性率.结果 方法A、方法B和方法C的精密度、线性范围、回收率均在可接受范围内,临床报告范围分别为0.8~920.0 nmol/L、1~4000 mg/L、3~1960 mg/L,参考区间均通过验证.方法B与方法A的相关性较好(R2=0.932),方法C和方法A的相关性较差(R2=0.631).相对于方法A,方法B对11.8%的样本有高估现象,方法C对13.7%的样本有高估现象、对3.1%的样本有低估现象.CAD组、PAD组、脑卒中组与正常对照组相比,3种方法的Lp(a)检测结果差异均有统计学意义(P<0.001).方法A在正常对照组中的阳性率较低,但3种方法的阳性率差异无统计学意义(P>0.05);方法B和方法C在CAD组和PAD组中的阳性率明显高于方法A(P<0.05);方法B在脑卒中组中的阳性率与方法A差异无统计学意义(P>0.05),而方法C则明显高于方法A(P<0.001).结论 方法A检测Lp(a)的颗粒浓度可溯源到SRM 2B,能更准确地反映样本Lp(a)水平;方法B和方法C检测Lp(a)的质量浓度,与Lp(a)颗粒浓度比较,高估了样本中的Lp(a)水平.检测方法的选择及判断限的确定对Lp(a)在心血管疾病、PAD以及脑卒中等疾病风险预测研究中的应用有较大影响.%Objective To evaluate the performance of a new lipoprotein(a)[Lp(a)] particle concentration assay(method A)and 2 kinds of Lp(a)mass concentration assays(method B and method C). Methods The precisions,linear ranges and clinical reportable ranges of the 3 methods were evaluated. The Lp(a)levels of 322 samples were determined by the 3 methods. Applying 75 nmol/L as the cut-off value for method A,and 300 mg/L for method B and method C,the positive rates of the 3 methods in coronary artery disease(CAD),peripheral artery disease(PAD),cerebral stroke and healthy control groups were compared. Results The precisions,linear ranges and recovery rates of the 3 methods were acceptable. The clinical reportable ranges of the 3 methods were 0.8-920.0 nmol/L,1-4000 mg/L and 3-1960 mg/L. Method B showed a good correlation with method A(R2=0.932), while method C showed a poor correlation with method A(R2=0.631). Compared to method A,Lp(a)levels were overestimated in 11.8% samples for method B and 13.7% samples for method C,and were underestimated in 3.1%samples for method C. Compared to healthy control group,Lp(a)levels of CAD,PAD and cerebral stroke groups all showed statistical significance(P<0.001). The positive rate of method A in healthy control group was low,and there was no statistical significance for the positive rates of the 3 methods(P>0.05). The positive rates of method B and method C in CAD and PAD groups were higher than those of method A(P<0.05). The positive rate of method B in cerebral stroke group had no statistical significance with that of method A(P>0.05),and that of method C was higher than that of method A(P<0.001). Conclusions Method A for Lp(a)particle concentration can be traced to standard reference material(SRM)2B,and can reflect Lp(a)level correctly. Method B and method C for Lp(a)mass concentration overestimate Lp(a)levels compared with particle concentration. The levels of Lp(a)for predicting the risks of cardio vascular disease,PAD and cerebral stroke can be affected by the selection of methods and cut-off values.
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