A new precipitation method with magnetic separation for high-density-lipoprotein cholesterol assay.

We describe a new precipitation method for high-density-lipoprotein cholesterol quantitation. The new method uses magnetic force instead of centrifugal force to separate high-density-lipoprotein from other lipoproteins that are fractioned with a precipitating reagent. The reagents used for the new method are the same as those for the conventional method except that magnetizable particles are included in the former. The magnetizable particles are used without any modifications. The correlation between the new and the centrifuge methods with dextran sulfate-magnesium chloride, sodium phosphotungstate-magnesium chloride and polyethylene glycol 6,000 were satisfactory (r = 0.990, 0.997 and 0.997, respectively). The new method, which can be combined with any precipitating reagents used in conventional methods, is very simple to perform and does not need any special equipment.