Accuracy and reproducibility of a quantitative electrophoresis of plasma lipoproteins: interlaboratory comparison and verification by ultracentrifugation

Fifty-three samples of sera from normal subjects and from patients with type IIa, IIb and IV hyperlipoproteinemia were shipped from Hannover to the collaborative laboratories in Vienna and Mannheim, which participated in the quantification of their lipoprotein fractions based on polyanion precipitation of electrophoretically separated lipoproteins followed by densitometric measurement of alpha-, prebeta- and beta-lipoproteins. Total serum cholesterol and cholesterol calculated from quantified lipoprotein fractions were highly correlated, the correlation coefficients ranged between r = 0.93–0.98. Furthermore, we found a high concordance comparing the beta-, prebeta- and alpha-cholesterol with data obtained from lipoprotein fractionation and subsequent cholesterol measurement by ultracentrifugation. The obtained correlation coefficients were always higher than r = 0.91. High accuracy and reproducibility of the quantitative lipoprotein electrophoresis justify its recommendation for wide use in the field of clinical chemistry.