Vohnout B, Vachulová A, Blazícek P, Dukát A, Fodor G, Lietava J
2nd Dept. of Internal Medicine, School of Medicine, Comenius University, Bratislava, Slovakia.
Vnitr Lek. 2008 Oct;54(10):961-4.
Due to limitations of the Friedewald formula, alternative methods for calculating low-density lipoprotein cholesterol (LDL-C) were suggested. We evaluated utility of these methods.
Ninety three subjects free of coronary heart disease were considered. LDL-C was measured by the homogeneous method, and calculated by the Friedewald formula LDL-C = TC-HDL-(TG/2.2) (LDL1) and alternative formulas LDL-C = 0.41 TC - 0.32 TG + 1.70 apoB - 0.27 (LDL2) and LDL-C = 0.94 TC - 0.94 HDL - 0.435 TG (LDL3).
All three formulas underestimated the measured LDL-C, both in the whole group and in subgroups according to TG levels (TG < 1.7 and in a range of 1.7-4.5 mmol/l, p < 0.001 for all). We found significantly higher bias for all three formulas in subjects with 1.7 < or = TG < 4.5 mmol/l levels. The Friedewald formula showed the lowest assay bias in all the groups investigated. The mean absolute bias for LDL1 was 7.6%, 18.3% for LDL2 and 13.6% for LDL3, respectively. Linear regression analysis showed correlation of calculated LDL-C values with the direct method in the range of r = 0.82 - 0.90 (p < 0.0001 for all, except of LDL2 in 1.7 < or = TG < 4.5 mmol/l group where p = 0.0011).
The Friedewald formula seems to be a better estimator of LDL-C in our study than the other two alternative formulas; however, it underestimated the LDL-C levels.
由于Friedewald公式存在局限性，有人提出了计算低密度脂蛋白胆固醇（LDL-C）的替代方法。我们评估了这些方法的实用性。
纳入93例无冠心病的受试者。采用匀相法测定LDL-C，并根据Friedewald公式LDL-C = TC - HDL - (TG/2.2)（LDL1）以及替代公式LDL-C = 0.41TC - 0.32TG + 1.70载脂蛋白B - 0.27（LDL2）和LDL-C = 0.94TC - 0.94HDL - 0.435TG（LDL3）进行计算。
在整个组以及根据甘油三酯（TG）水平划分的亚组中（TG < 1.7以及在1.7 - 4.5 mmol/l范围内），所有三个公式均低估了实测的LDL-C（所有p < 0.001）。我们发现，在TG水平为1.7≤TG < 4.5 mmol/l的受试者中，所有三个公式的偏差均显著更高。在所有研究组中，Friedewald公式显示出最低的测定偏差。LDL1的平均绝对偏差分别为7.6%，LDL2为18.3%，LDL3为13.6%。线性回归分析显示，计算得到的LDL-C值与直接法之间的相关性在r = 0.82 - 0.90范围内（除1.7≤TG < 4.5 mmol/l组中的LDL2，其p = 0.0011外，所有p < 0.0001）。
在我们的研究中，Friedewald公式似乎比其他两个替代公式更能准确估算LDL-C；然而，它低估了LDL-C水平。
