High-density lipoprotein cholesterol assay by magnesium dextransulphate precipitation

A method for determination of high-density lipoprotein cholesterol (HDL-C) is evaluated: after precipitation of low and very low lipoprotein cholesterol in serum by magnesium dextransulphate, HDL-C is determined by an enzymatic method. The precision of the method was good: coefficient of variation 4%. The accuracy was good, evaluated by correlating HDL-C results from the present assay to the results obtained from three other HDL-C assays (n = 17): ultracentrifugation r = 0.91, phosphotungstate/MgCl2 r = 0.98, and alpha-lipoprotein determination by electrophoresis r = 0.91 (p less than 0.01). Repeated analysis showed that serum may be kept at 4 degrees C for 1 month, at -20 degrees C for 2 months, and requires -80 degrees C for longer storage. Ten patients with acute myocardial infarction showed significantly lower HDL-C from day 4 in the acute phase and during the first 3 months follow up (p less than 0.05). Eighty patients with peripheral vascular disease, who were compared to a group of matched controls, also showed significantly decreased serum HDL-C (p less than 0.01). The present HDL-C assay is easy, fast and reliable and is considered a valuable clinical test.