RESUMO
OBJECTIVE: To compare the advantages and disadvantages of electrophoresis with the traditional method in measuring lipoprotein cholesterol in serum. METHODS: Four lipoprotein cholesterols were determined by the Helena electrophoretic system. Quantification of high density lipoprotein-choleterol(HDL-C) was performed by phosphotungstate-magnesium precipitation or direct HDL-C assay. The concentration of low density lipoprotein-cholesterol (LDL-C) was calculated by F-equation. RESULTS: Four lipoprotein zones were segregated distinctly by the electrophoretic method. Lp(a) zone appeared only in 6 out of 68 normal samples (8.82%). Reference values of HDL-C, Lp(a)-C, VLDL-C, and LDL-C in serum were 1.16-2.19, 0-0.22, 0.07-0.47, and 1.86-3.46 mmol.L-1, respectively. When comparing the results by electrophoresis with those by the precipitation method for HDL-C, no significant difference was found (P > 0.05); but there was a significant difference between electrophoresis and F-formula calculation for LDL-C (P < 0.05). When comparing results of electrophoresis with the direct method, we found significant differences in both HDL-C and LDL-C (P < 0.01). CONCLUSION: F-formula used for calculating LDL-C is not appropriate to clinical application. Electrophoresis allows the quantification of HDL-C, VLDL-C, LP(a)-C, and LDL-C. The method is simple, convenient, and appropriate to routine application.
