title: High correlation but lack of agreement between direct high-performance gel chromatography analysis and conventional indirect methods for determining lipoprotein cholesterol.
abstract: Low-density lipoprotein-cholesterol (LDL-C) is currently estimated clinically by using the Friedewald formula, when plasma triglycerides are < 4000 mg/L, or as the difference between infranatant and high-density lipoprotein-cholesterol (HDL-C) values after ultracentrifugation of plasma at native density, when plasma triglycerides are > or = 4000 mg/L (beta quantification). HDL-C is measured by selective precipitation of apolipoprotein B-containing lipoproteins from whole plasma or from the density > 1.006 kg/L infranatant. We compared these conventional methods for LDL-C and HDL-C with "high-performance" gel chromatography (HPGC), a method that directly and simultaneously measures both LDL-C and HDL-C in a single, microliter volume of plasma. Not surprisingly, we found that the results by all these methods were highly correlated. However, LDL-C values were significantly higher and HDL-C values significantly lower by the direct HPGC method than by the conventional methods (paired t-test). In addition, both Bland-Altman plots and concordance correlation analyses indicated lack of agreement between the methods' results in the majority of patients' subgroups.
authors.affiliation: Cardiac and Vascular Diseases, Parke-Davis Pharmaceutical Research Div., Warner-Lambert Co., Ann Arbor, MI 48105, USA. kraus01@aa.wl.com
authors.forename: B R
authors.initials: BR
authors.lastname: Krause
authors.forename: N J
authors.initials: NJ
authors.lastname: Schork
authors.forename: K A
authors.initials: KA
authors.lastname: Kieft
authors.forename: M P
authors.initials: MP
authors.lastname: Smith
authors.forename: J J
authors.initials: JJ
authors.lastname: Maciejko
mesh_terms: D001055:Apolipoproteins B / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D008433:Mathematics; D014280:Triglycerides / Q000097:blood
chemical_list: D001055:Apolipoproteins B; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D014280:Triglycerides