Separation of serum high-density lipoprotein for cholesterol determination: ultracentrifugation vs precipitation with sodium phosphotungstate and magnesium chloride.

We compared two methods for separation of serum high-density lipoprotein: selective precipitation with sodium phosphotungstate and magnesium chloride, and ultracentrifugation in sodium chloride solution (relative density 1.063). When the cholesterol content (determined enzymically with a centrifugal analyzer) of fractions obtained by each method was compared (ultracentrifugation = x), the correlation coefficient was 0.97; y = 1.01x - 11.2 mg/L; p less than 0.05; n = 54. The within-day and between-day coefficients of variation for this method were 1.1 and 4.0%, respectively. Reference intervals for high-density lipoprotein cholesterol in subpopulations categorized by age and sex were based on data obtained from volunteer blood donors.