ANALYTICAL PERFORMANCE AND CLINICAL UTILITY OF A DIRECT LDL-CHOLESTEROL ASSAY IN A HYPERLIPIDEMIC PEDIATRIC POPULATION

This study compares a neu latex immunoseparation method for the direct determination of plasma low-density lipoprotein cholesterol (LDL-C) w ith the reference procedure for LDL-C (beta-quantification) in a pedia tric hyperlipidemic population, The direct LDL-C assay has a mean bias of -98 mg/L in a fasting group (n = 96) of patients (mean triglycerid es 1057 +/- 720 mg/L) and a bias of +177 mg/L in a nonfasting group (n = 42, mean triglycerides 4854 +/- 5457 mg/L). The mean total analytic al error calculated from our data is 13.8%, The direct LDL-C assay and the commonly used Friedewald calculation respectively classified 81% and 84% of fasting patients correctly, according to the cutoffs of 110 0 and 1300 mg/L for LDL-C set by the National Cholesterol Education Pr ogram for pediatric patients, Of combined fasting and nonfasting patie nts, 80% were correctly classified by the direct LDL-C assay, Therefor e, despite several analytical shortcomings, the direct LDL-C assay may be useful in managing hyperlipidemic children without the need for a fasting specimen.