Mackness Mike, Hughes Elizabeth
Division of Cardiovascular Sciences, University of Manchester, Department of Medicine, Manchester Royal Infirmary, Manchester M13 9WL, UK.
Ann Clin Biochem. 2009 Jul;46(Pt 4):311-5. doi: 10.1258/acb.2009.08166. Epub 2009 Jun 1.
Elevated Lipoprotein(a) concentrations are a risk factor for coronary heart disease; however, methodological problems have prevented its introduction to routine clinical practice.
Thirty-six laboratories each assayed 20 samples (the same 20 in each laboratory) using two different Lp(a) kits per laboratory, randomly assigned from the total of 12 used in the study.
The duplicate error, i.e. the error between-duplicate analyses for each sample, for all kits was small, indicating all kits had a good precision for all the assays. However, there was a very large variation between the kits in the Lp(a) concentration assigned to a sample that could be over 100%. All methods showed a negative or positive bias as the concentration of Lp(a) increased. Most worryingly, as used in this study, several Lp(a) kits detected Lp(a) in a solution of 5% bovine serum albumin in phosphate-buffered saline. The between-laboratory variation in Lp(a) concentration measured using the same kit was very large, e.g. for a sample with a mean concentration of 78.8 mg/dL Lp(a) the between-laboratory variation was 29.7 mg/dL (37.7%). Even with samples with a relatively low Lp(a) concentration of 16.0 mg/dL had a between-laboratory variation of 12.3 mg/dL (76.8%).
There is wide variability in reported Lp(a) concentrations, assayed in the same sample, using different Lp(a) assays. At the present time these differences prevent the use of Lp(a) as a routine diagnostic tool.
脂蛋白(a)浓度升高是冠心病的一个危险因素；然而，方法学问题阻碍了其在常规临床实践中的应用。
36个实验室各自使用两种不同的脂蛋白(a)检测试剂盒检测20个样本（每个实验室检测相同的20个样本），这些试剂盒从研究中使用的总共12种试剂盒中随机分配。
所有试剂盒的重复误差，即每个样本重复分析之间的误差都很小，表明所有试剂盒对所有检测都具有良好的精密度。然而，不同试剂盒对同一样本所测定的脂蛋白(a)浓度存在非常大的差异，可能超过100%。随着脂蛋白(a)浓度的增加，所有方法均显示出负偏差或正偏差。最令人担忧的是，在本研究中使用时，几种脂蛋白(a)试剂盒在磷酸盐缓冲盐水中5%牛血清白蛋白溶液中检测到了脂蛋白(a)。使用相同试剂盒测量的脂蛋白(a)浓度在实验室间的差异非常大，例如，对于一个平均浓度为78.8mg/dL脂蛋白(a)的样本，实验室间差异为29.7mg/dL（37.7%）。即使是脂蛋白(a)浓度相对较低的16.0mg/dL的样本，实验室间差异也有12.3mg/dL（76.8%）。
使用不同的脂蛋白(a)检测方法对同一样本进行检测时，所报告的脂蛋白(a)浓度存在很大差异。目前，这些差异阻碍了将脂蛋白(a)用作常规诊断工具。
