Background Beta-quantification (BQ) is the reference method for LDL-C but is not widely available. It is difficult, therefore, for clinical laboratories to independently assess the accuracy of their methods for either calculating or directly measuring LDL-C. Our goal was to investigate if an interrelationship between the tests in the standard lipid panel could be used to compare the performance of different LDL-C methods against BQ, specifically in samples with hypertriglyceridemia, a major cause of bias for LDL-C testing. Methods BQ results from Mayo Medical Labs (n=39,667) and the NIH (n=18,338) were used to identify a linear relationship by least-squares regression analysis between lipid panel test results and LDL-C to facilitate a statistical comparison between different LDL-C methods. Results It is well established that the number of VLDL particles increases as TG increases, because VLDL is the main carrier of TG. As a consequence, the ratio of LDL-C to non-HDL-C is inversely related to TG, which can be made linear by taking the square root of TG (Figure). Nearly identical regression equations were found for this relationship, using two different BQ datasets. When LDL-C was calculated by either Sampson equation, the LDL-C/non-HDL-C regression lines nearly overlapped with the one for BQ. In contrast, the Martin equation showed a positive bias with increasing TG, whereas the Friedewald equation showed a negative bias, consistent with past reports on their LDL-C biases with hypertriglyceridemia. In the UKBiobank, the Beckman direct LDL-C showed a positive bias for TG, which was confirmed in CAP proficiency test surveys. By simulation analysis, approximately 80 samples with high (>200 mg/dL) and low (<100 mg/dL) TG is statistically sufficient to assess if the LDL-C/non-HDL-C regressions lines of LDL-C methods differ from BQ. Conclusions The LDL-C/non-HDL-C ratio method is a simple way to examine LDL-C methods for bias on hypertriglyceridemic samples.

中文翻译：

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A-210 Ldl-c 与非 HDL-c 比率法：确定高甘油三酯样品上 LDL-c 方法偏差的简单方法


背景 β 定量 （BQ） 是 LDL-C 的参考方法，但尚未广泛使用。因此，临床实验室很难独立评估其计算或直接测量 LDL-C 的方法的准确性。我们的目标是研究标准脂质组中测试之间的相互关系是否可用于比较不同 LDL-C 方法与 BQ 的性能，特别是在高甘油三酯血症的样品中，高甘油三酯血症是 LDL-C 测试偏倚的主要原因。方法 使用梅奥医学实验室 （n=39,667） 和 NIH （n=18,338） 的 BQ 结果，通过血脂组测试结果与 LDL-C 之间的最小二乘回归分析来确定线性关系，以促进不同 LDL-C 方法之间的统计比较。结果 由于 VLDL 是 TG 的主要载体，因此 VLDL 颗粒的数量随着 TG 的增加而增加。因此，LDL-C 与非 HDL-C 的比率与 TG 成反比，可以通过取 TG 的平方根来使其呈线性（图）。使用两个不同的 BQ 数据集，为这种关系找到了几乎相同的回归方程。当通过任一 Sampson 方程计算 LDL-C 时，LDL-C/非 HDL-C 回归线几乎与 BQ 的回归线重叠。相比之下，Martin 方程显示 TG 增加的正偏差，而 Friedewald 方程显示负偏差，与过去关于高甘油三酯血症 LDL-C 偏差的报告一致。在英国银行，贝克曼直接 LDL-C 显示 TG 的正偏倚，这在 CAP 能力测试调查中得到了证实。 通过模拟分析，大约 80 个具有高 （>200 mg/dL） 和低 （<100 mg/dL） TG 的样品在统计学上足以评估 LDL-C 方法的 LDL-C/非 HDL-C 回归线是否与 BQ 不同。结论 LDL-C/非 HDL-C 比值法是检查 LDL-C 方法对高甘油三酯血症样本偏倚的一种简单方法。