Total automated method for determination of cholesterol concentration in high density lipoprotein by heparin-magnesium-albumin precipitation.

We describe an automated procedure for determination of high-density-lipoprotein cholesterol in serum by use of heparin-MgCl2-albumin reagent. 'AutoAnalyzer' II equipment was used in which high-density lipoprotein was separated from precipitate containing very-low and low-density lipoproteins by filtering on-line across a cellulose acetate membrane. Cholesterol concentration was measured by the enzymic method of Allain. Good correlation was obtained using the automated method compared to the heparin-MgCl2-albumin (r=0.99) or sodium phosphotungstate-MgCl2 procedure (r=0.97). Contamination was minimal with a contamination coefficient lower than 2.5%. The method presented was linear (0 to 2.50 mmol/1) and could be applied to lipemic samples with a coefficient of variation better than 3%. This study showed thus that this new procedure was suitable for routine work with a good rate (60 samples/h) in almost any laboratory.