Enzymatic determinations of cholesterol in high-density-lipoprotein fractions prepared by a precipitation technique.

Abstract

An enzymatic method for cholesterol in serum [Clin. Chem. 20, 470 (1974)] was initially found to be unsatisfactory for measuring cholesterol in high-density-lipoprotein fractions prepared by precipitation with Mn2+. A fine precipitate formed in the cuvette and cholesterol values were falsely increased. We describe a simple, convenient method for circumventing these problems. An ethylenediaminetetraacetate solution is used to reconstitute the enzymatic reagent. Cholesterol values by this procedure correlated with those obtained by the Lipid Research Clinic's procedure for the same lipoprotein fraction preparations (regression slope, .998; Y-intercept, 8.9 mg/liter; correlation coefficient, .984; standard error of the estimate, 16.8 mg/liter). Precision of the assay, including the precipitation step, was calculated. The SDwithin day was 9.7 mg/liter and SDoverall was 23.7 mg/liter. Results for total cholesterol with the modified reagent were linearly related to concentrations exceeding 4 g/liter, thereby permitting determination of high-density-lipoproteins and total cholesterol in a single run.

Lipid Levels in Very Low Birthweight Preterm Infants

“…The method of Laurel1 & Tibbling (9) was used to measure plasma free fatty acid concentration. High-density lipoprotein cholesterol (HDL-C) and its subfractions were measured by the precipitation methods of Steele et al (10) and Khan et al (1 1). A figure for very-low-density lipoprotein cholesterol and low-density lipoprotein cholesterol together (VLDL+ LDL-C) was obtained by subtracting the value for HDL-C from that of T-C.…”

Screening of Cord Blood Low‐density‐lipoprotein Cholesterol in the Diagnosis of Familial Hypercholesterolaemia: A Study of 2000 Infants

“…Artefactually high values for HDL-C which may occur if manual enzymatic methods are used (29), are not obtained when the enzymatic method is used on a centrifugal analyser (see appendix). The value of LDL-C was derived using the formula LDL-C = TC-(TG/5 + HDL-C).…”

Association of n‐6 long‐chain polyunsaturated fatty acids to −866 G/A genotypes of the human uncoupling protein 2 gene in obese children

“…Triacylglycerol and cholesterol were determined with an enzymatic kit (Boehringer Mannheim, Mannheim, Germany). High‐density lipoprotein cholesterol was measured by the precipitation method of Steele et al (9).…”