Abstract

RAMIREZ, A; PISTILLI, N; ECHAGUE, G  and  ZAVALA DE MELGAREJO, MV. Comparison between the analytical determination of LDL-cholesterol and its estimation by calculation. Mem. Inst. Investig. Cienc. Salud [online]. 2005, vol.3, n.1, pp.43-46. ISSN 1812-9528.

LDL-cholesterol(LDL-C) is one of the principal markers of atherogenic risk and is used for preventive aims. The determination of this marker by calculation is frequent in laboratories. Thus, the aim of this study was to compare Friedewald formula with an analytical method based on the precipitation of LDL with polyvinyl sulphate (PVS) described by Kerscher. The cholesterol linked to these proteins was determined using the enzymatic colorimetric system of Trinder. The cholesterol linked to LDL (LDL-Ca) was obtained by the difference between total cholesterol and the one determined in the supernatant. This result was compared with the method of calculation for LDL-C estimation. All values of triglycerids > or equal to 400 mg/dl were eliminated. In the normolipemic patients, the mean LDL-Cc was 95 ± 29 mg/dl and for LDL-Cc 99 ± 26 mg/dl. The correlation coefficient was r=0.91 (p <0.001). In hypercholesterolemic patients, mean LDL-Ca was 170 ± 22 mg/dl and for LDL-Cc 160 ± 21 mg/dl; the correlation coefficient was r=0.87 (p <0.001). In hypertriglyceridemic patients, mean LDL-Ca was 122 ± 42 mg/dl and LDL-Cc 106 ± 41 mg/dl with a correlation coefficient of r= 0.92 (p <0.001). Based in these results, we could emphasize that the analytical method is rapid, precise and easy to use in the clinical laboratory and that both methods are comparable for triglyceride values lower than 400 mg/dl.

Keywords : LDL-cholesterol; Triglycerids; Friedewald; Polyvinyl sulphate.

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