Measurement of total HDL, HDL2 and HDL3 by dextran sulfate-MgCl2 precipitation technique in human serum.

We describe a simple and reliable method for determination of total HDL, HDL2, and HDL3 by a precipitation technique using dextran-sulfate (Mr 50,000)-Mg2+. A combined solution of dextran sulfate and Mg2+ at their respective final concentration of 0.9 g/l and 27 mmol/l was optimal for separating total HDL from the other lipoproteins. The present method compares favorably with a heparin-MnCl method (r = 0.998). The HDL was further resolved into HDL2 and HDL3 by addition of a combined solution of dextran sulfate and Mg2+ (1.5 m/l and 10 g/l) to the total HDL solution. Comparison of this precipitation method with the well-established ultracentrifugation method yielded the mean correlation coefficient of 0.941 and 0.869 for HDL2 and HDL3, respectively.