均相法和VAP分离相法检测低密度脂蛋白胆固醇水平的比较

Comparative analysis of homogeneous phase and vertical auto profile separation phase methods for detecting low-density lipoprotein cholesterol levels

目的观察均相法和垂直密度梯度离心全自动血脂谱(VAP)分离相法检测血浆标本低密度脂蛋白胆固醇(LDL-C)结果不一致性,并探讨其原因,为准确定量检测血浆LDL-C水平提供实验依据。方法收集2022年1月至2023年1月宁波市鄞州中医院内分泌科糖尿病颈动脉斑块患者血浆标本360份,同时采用均相法和VAP分离相法检测LDL-C水平,VAP分离相法通过软件自动计算标本离心后的LDL-C曲线下面积作为LDL-C水平(LDL-C_(VAP)),均相法通过特殊表面活性剂法直接检测LDL-C水平(LDL-C_(均相))。360份标本根据LDL-C_(均相)与LDL-C_(VAP)相对偏差程度,分为LDL-C_(均相)与LDL-CvAP一致组(A组)和不一致组(B组),B组又分为LDL-C_(均相)偏高(B1)组和偏低(B2)组,B1和B2组根据相对偏差大小又分为B1-1、B1-2和B1-3以及B2-1组。统计各组标本百分比,各组标本脂蛋白a胆固醇[Lp(a)-C]、中密度脂蛋白胆固醇(IDL-C)、Lp(a)-C和IDL-C之和[Lp(a)-C+IDL-C]、极低密度脂蛋白胆固醇(VLDL-C)、高密度脂蛋白胆固醇(HDL-C)以及总胆固醇(TC)和总三酰甘油(TG)水平。结果360份标本LDL-C_(均相)明显大于LDL-CvAP,P<0.01。B组标本百分比明显高于A组,B1组明显高于B2组,P<0.05。B1组各组标本Lp(a)-C、IDL-C以及Lp(a)-C+IDL-C水平均明显高于A组,P<0.01。360份标本LDL-C_(均相)与LDL-C_(VAP)相对偏差与标本Lp(a)-C、IDL-C、Lp(a)-C+IDL-C水平呈明显正相关,相关系数最大指标为Lp(a)-C+IDL-C,P<0.01。结论糖尿病颈动脉斑块患者血浆标本均相法检测LDL-C与VAP分离相法检测结果明显不一致,主要表现为均相法检测结果偏高。标本Lp(a)-C+IDL-C水平越高,均相法和VAP分离相法检测相对偏差越大。均相法检测LDL-C结果偏高原因,可能与均相法检测LDL-C结果包含了无法消除的Lp(a)和IDL携带的胆固醇有关。VAP分离相法可作为准确检测不含Lp(a)-C和IDL-C的真正LDL-C水平的方法。

Objective To investigate the reasons for the inconsistent results between the vertical auto profile(VAP)method and bio-chemical homogeneous phase(BHP)method in detecting plasma low-density lipoprotein cholesterol(LDL-C),and provide experimen-tal basis for the accurate and quantitative detection of plasma LDL-C levels.MethodsA total of 360 plasma samples from diabetes mellitus patients combined with carotid plaque admitted to the Department of Endocrinology of Ningbo Yinzhou Hospital of Traditional Chinese Medicine during January,2022 and January,2023 were collected.The LDL-C levels of these samples were detected by the VAP method and BHP method,respectively.The VAP method uses software to automatically calculate the area under the LDL-C curve after centrifugation of the sample as the LDL-C level(LDL-C_(VAP))and the BHP method directly detects the LDL-C level(LDL-C_(BHP))by the special surfactant method.360 samples were divided into the consistent group(group A)and inconsistent group(group B)ac-Cording to the relative deviation between the LDL-CBHp and LDL-C_(VAP) methods.Group B was further divided into the LDL-CBHp on the high side group(Group B1)and LDL-CBHp on the low side group(Group B2).Groups B1 and B2 were divided into B1-1,B1-2,B1-3 and B2-1 groups based on the degree of relative deviation.The percentages of samples and levels of lipoprotein a cholesterol[Lp(a)-C],intermediate-density lipoprotein cholesterol(IDL-C),Lp(a)-C and IDL-C[Lp(a)-C+IDL-C],very low-density lipo-protein cholesterol(VLDL-C),total cholesterol(TC)and total triglyceride(TG)in each group were compared.Results The LDL-CBHp levels of 360 samples were significantly higher than that of LDL-C_(VAP)(P<0.01).The percentage of samples in group B was significantly higher than that in group A,and that of group B1 was significantly higher than that of group B2(P<0.05).The levels of Lp(a)-C,IDL-C and Lp(a)-C+IDL-C in groups B1-1,B1-2,and B1-3 were significantly higher than those in group A(P<0.01).The relative deviation between LDL-C_(BHP) and LDL-C_(VAP) in 360 samples was significantly positively correlated with the levels of Lp(a)-C,IDL-C,and Lp(a)-C+IDL-C(P<0.01).The maximum correlation coefficient was found in Lp(a)-C+IDL-C.Conclusion The results of plasma LDL-C in diabetes mellitus patients combined with carotid plaque detected by the BHP method are significantly different from those detected by the VAP method,which mainly shows that the results of the BHP method are on the high side.The higher the level of plasma Lp(a)-C+IDL-C,the greater the relative deviation between the BHP method and VAP method.The reason for the high results of LDL-C detected by the BHP method may be related to the fact that LDL-CBHp contains irremovable Lp(a)-C and cholesterol carried by IDL-C.The VAP method can be used as an accurate method for detecting real LDL-C without Lp(a)-C and IDL-C.