Development of Formulas for Estimation of Cholesterol Levels in Major Serum Lipoproteins Separated by Agarose Gel Electrophoresis

Background/aim: Electrophoresis is useful for examining the lipoprotein fraction patterns. A simultaneous and cost-effective addition of cholesterol levels in each lipoprotein fraction to the lipoprotein patterns can more assist clinical decision-making. This study' aim was to develop the formulas for estimating the fractionated lipoproteins cholesterol levels in a recent system, the agarose gel Sebia HYDRAGEL LIPO+Lp(a) electrophoresis. Methods: Serum samples were analyzed by two Sebia electrophoresis, HYDRAGEL LIPO+Lp(a) and the quantitative HYDRAGEL LDL/HDL-CHOL Direct methods. The formulas for estimation of relative cholesterol (%) of individual lipoprotein fractions were developed using linear regression models. Thereafter, the calculated lipoproteins cholesterol values by multiplying the relative cholesterol with total cholesterol concentrations were compared with the standardized enzymatic assayed values. Results: The equations for calculating % relative cholesterol (y) from % relative lipoprotein (x) were y=x-8, x+21 and 0.75x-6.5 for high-density lipoprotein (HDL), low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) fractions, respectively. Regression statistics obtained between the calculated assays (y) and the standardized enzymatic assays (x') in samples with and without Lp(a) were y=1.07x'- 0.18 and 1.06x'-0.06, respectively for HDL-cholesterol, y=0.90x'+0.32 and 0.92x'+0.29 for LDL-cholesterol, and y=0.85x'-0.03 and 0.95x'+0.02 for VLDL-cholesterol. Conclusions: The proposed formulas can provide a reliable estimation of cholesterol levels in each major lipoprotein fraction by the HYDRAGEL LIPO+Lp(a) electrophoresis. Further studies with its application are needed.