Comparison of two direct methods for HDL cholesterol measurement with an indirect precipitation method in diabetic patients.

The conventional precipitation method for measuring HDL cholesterol involves a centrifugation step which prevents automation of the method. Several methods have been introduced for measuring HDL cholesterol without the need for a centrifugation step. These new methods are therefore automatable and can process a large number of samples in a short period of time. Measuring HDL cholesterol is an important aspect of management of diabetes mellitus. In this study, we compared 2 direct methods for measuring HDL cholesterol with a conventional precipitation technique in 63 patients with either Type 1 or Type 2 diabetes mellitus. Both direct methods showed acceptable precision but they both showed positive bias compared to the conventional precipitation method. The greatest degree of bias occurs at low HDL cholesterol levels, which are more important for Type 2 patients. Such differences may affect cardiovascular risk calculation in patients with diabetes. Further studies are required to investigate if a correction factor needs to be introduced when these direct assays are used to measure HDL cholesterol in patients with Type 2 diabetes mellitus.