Homogeneous HDL-cholesterol assay versus ultracentrifugation/dextran sulfate-Mg 2+ precipitation and dextran sulfate-Mg 2+ precipitation in healthy population and in hemodialysis patients

Abstract

Objectives: To evaluate the analytical performance of a new homogeneous HDL-cholesterol assay (Olympus Diagnostica). To investigate possibly discrepant results in chronic hemodialysis patients who commonly exhibit quantitative and qualitative lipoprotein abnormalities, responsible for atherogenic complications in these patients. Design and methods: Serum samples were collected from 50 healthy subjects and 65 chronic hemodialysis patients. HDL-C levels measured by the homogeneous assay were compared with the routine dextran sulfate-Mg 2+ precipitation method and the ultracentrifugation/dextran sulfate-Mg 2+ precipitation as reference method. Results: The homogeneous assay was linear up to at least 220 mg/dL. The analytical precision was estimated with three different sets of commercial controls and one set of human pooled serum control. The within-day CV ranged between 1.7% and 3.8% and the between-day CV ranged between 1.0% and 2.3%. HDL-C values in both populations correlated highly with the dextran sulfate-Mg 2+ precipitation method and the ultracentrifugation/dextran sulfate-Mg 2+ precipitation method (r ≥ 0.96, bias between −0.9 and 2.3 mg/dL). Lipemia up to triglyceride concentration of 600 mg/dL did not alter the HDL-C value. Conclusions: The homogeneous assay for HDL-C (Olympus) uses much less sample, is accurate and convenient to handle, and allows full automation. The test should considerably facilitate the screening of individuals at an increased risk of cardiovascular disease, including hemodialysis patients.