Performance characteristics of a microfluidic Lab-on-Chip electrophoresis system for high-density lipoprotein (HDL) subfraction separation and measurement.

BACKGROUND: High-density lipoprotein (HDL) is believed to be protective against coronary heart disease (CHD). HDL is comprised of different subfractions. Of these, HDL 2b is believed to be the most important in preventing CHD. Current methods for HDL subfraction measurements are not standardized and often exhibit poor analytical performance, which can limit their usefulness in clinical practice. METHODS: We have developed a microfluidic Lab-on-Chip electrophoresis system for serum HDL subfraction measurements. Linear polymers are used as a sieving buffer for HDL particle separation. Nine samples and two controls can be analyzed in 30 min. The percent HDL 2b that comprises total high-density lipoprotein cholesterol (HDL-C) is reported. RESULTS: Samples with HDL-C of 0.259-2.072 mmol/L could be evaluated for percent HDL 2b with coefficient of variations (%CVs) below 8%. Total precision was typically below 1.5% and linearity was observed between 8% and 32% HDL 2b. Measurements were not affected by many therapeutic and biological compounds. Consistent results were obtained by three laboratories and showed r(2) values between 0.93 and 0.95. CONCLUSIONS: The assay allows for easy and reproducible measurement of percent HDL 2b. The experimental procedure and small size of the instrumentation needed for measurement make it viable in clinical settings.