IMMUNOSEPARATION METHOD FOR MEASURING LOW-DENSITY-LIPOPROTEIN CHOLESTEROL DIRECTLY FROM SERUM EVALUATED

Low-density lipoprotein (LDL) cholesterol can not be calculated from o ther lipid measurements when samples are obtained from nonfasting indi viduals or when triglycerides are greater than or equal to 4.0 g/L. We have evaluated a direct LDL cholesterol assay for analyzing 115 fresh serum samples obtained from fasting and nonfasting dyslipidemic patie nts with triglycerides less than or equal to 35.85 g/L, who were recei ving diet and (or) drug treatments. Results were highly correlated wit h those by ultracentrifugation (r = 0.97), with a mean/median bias of -2.9%/0.7% (-0.001/0.010 g/L) and an absolute bias of 9.5%/6.4% (0.119 /0.090 g/L). The assay correctly classified LDL cholesterol concentrat ions <1.30 g/L 81% of the time, 1.30-1.60 g/L 76% of the time, and gre ater than or equal to 1.60 g/L 94% of the time. Precision studies prov ided within- and between-run CVs in the range of 1.2-3.8% and 2.0-5.1% , respectively. Our data indicate that this assay is an accurate metho d for measuring LDLC directly from fresh serum obtained from fasting o r nonfasting subjects with a wide range of triglyceride values.