Jensen Tonny, Truong Quan, Frandsen Merete, Dinesen Bo, Stender Steen
Steno Diabetes Center, Gentofte, Denmark.
Diabetes Care. 2002 Nov;25(11):1914-8. doi: 10.2337/diacare.25.11.1914.
To compare direct-measured HDL cholesterol with HDL cholesterol measured by a precipitation method.
We compared a homogeneous assay for direct HDL cholesterol analysis with the phosphotungstic acid magnesium chloride precipitation method in 55 type 1 diabetic patients, 70 type 2 diabetic patients, and 82 nondiabetic normal control subjects with plasma triglyceride levels <4.6 mmol/l. The cholesterol content of HDL determined by the direct assay was overall 0.1 mmol/l higher in all three groups than HDL cholesterol measured after precipitation, but the two methods were closely correlated (r(2) = 0.98, P < 0.001).
HbA(1c), blood glucose, serum albumin, serum bilirubin, or triglyceride did not influence the differences of the two HDL cholesterol measurements. Because we have previously shown HDL cholesterol isolated by phosphotungstic acid precipitation to be lower than that by ultracentrifugation, the positive bias found in this study was expected. It seems that the direct HDL cholesterol assay reacts with apolipoprotein (apo) B-containing lipoproteins in the fraction with a density of >1.063; these apo B-containing lipoproteins are suggested to be coprecipitated with the phosphotungstic acid method. We also measured LDL cholesterol directly by a LDL cholesterol plus method and found no significant differences between this method and LDL cholesterol calculated from Friedewald's formula.
Direct homogeneous assay for HDL cholesterol determination in diabetic patients seems not to exhibit a negative bias, in contrast to the precipitation method, when compared with the ultracentrifugation method. In addition, the direct assay saves time and is not influenced by type of diabetes or degree of metabolic control.
比较直接测定的高密度脂蛋白（HDL）胆固醇与通过沉淀法测定的HDL胆固醇。
我们在55例1型糖尿病患者、70例2型糖尿病患者和82例血浆甘油三酯水平<4.6 mmol/l的非糖尿病正常对照受试者中，将用于直接HDL胆固醇分析的均相测定法与磷钨酸氯化镁沉淀法进行了比较。直接测定法测定的HDL胆固醇含量在所有三组中总体上比沉淀后测定的HDL胆固醇高0.1 mmol/l，但两种方法密切相关（r² = 0.98，P < 0.001）。
糖化血红蛋白（HbA₁c）、血糖、血清白蛋白、血清胆红素或甘油三酯均未影响两种HDL胆固醇测量值的差异。因为我们之前已表明通过磷钨酸沉淀分离的HDL胆固醇低于通过超速离心法分离的HDL胆固醇，所以本研究中发现的正偏差是预期的。似乎直接HDL胆固醇测定法与密度>1.063的部分中含载脂蛋白（apo）B的脂蛋白发生反应；这些含apo B的脂蛋白被认为会与磷钨酸法共沉淀。我们还通过LDL胆固醇加法定量直接测量了低密度脂蛋白（LDL）胆固醇，发现该方法与根据弗里德瓦尔德公式计算的LDL胆固醇之间无显著差异。
与超速离心法相比，糖尿病患者中用于测定HDL胆固醇的直接均相测定法与沉淀法相比似乎没有负偏差。此外，直接测定法节省时间，且不受糖尿病类型或代谢控制程度的影响。
