Which method is considered the reference method for HDL cholesterol measurement?

The reference method for measuring HDL cholesterol is ultracentrifugation of plasma in a potassium bromide solution. This technique is considered the gold standard because it effectively separates lipoproteins based on their density. In this method, the plasma is subjected to high-speed centrifugation, resulting in the separation of lipoproteins into distinct fractions, where the HDL cholesterol can be isolated. Once separated, HDL cholesterol concentration can be accurately measured.

This method is preferred due to its specificity and reliability in determining HDL cholesterol levels without interference from other lipoproteins, distinguishing it from many other assays that might not offer the same level of accuracy. The Abell-Kendall method primarily focuses on total cholesterol measurement rather than specifically measuring HDL cholesterol, while the glycerol kinase assay may not isolate HDL specifically. The sulfated cyclodextrin method is an alternative that can measure HDL cholesterol but is not regarded as the reference method in the same way as ultracentrifugation. Therefore, the ultracentrifugation method's established use as the standard makes it the correct choice in this context.