Reference intervals for cholesterol and triglyceride in HDL subfractions in an adult Spanish population using a...

Quantification of cholesterol and triglyceride concentration within high-density lipoprotein (HDL) subfractions may provide a better prediction of cardiovascular disease risk than total HDL cholesterol serum concentration. However, its clinical application is limited by the lack of methodological standardization and absence of population-specific reference intervals (RIs), which restrict individualized advanced cardiovascular risk stratification. The objective was to establish RIs for HDL2 cholesterol (HDL2-C) and HDL3 cholesterol (HDL3-C) concentrations, and for HDL3 triglyceride (HDL3-TG) concentrations, in a Spanish adult population using a single-step precipitation method.

This study was conducted in two phases. In the first phase, a comprehensive analytical performance evaluation of the single-step precipitation method was performed. Secondly, RIs were derived based on 198 apparently healthy individuals aged 18-68 years from a Spanish population. Sex and age-partitioning was evaluated and RIs were calculated according to CLSI EP28-A3C Guidelines.

The single-step precipitation method showed a satisfactory analytical performance. For males, RIs were: HDL2-C: 0.267-0.908 mmol/L; HDL3-C: 0.716-1.323 mmol/L and HDL3-TG: 0.215-0.385 mmol/L. For females, RIs were: HDL2-C: 0.298-1.022 mmol/L; HDL3-C: 0.739-1.538 mmol/L and HDL3-TG: 0.188-0.350 mmol/L (Table 2). Additional age partitioning using a 45-year cut-off was required for HDL2-C in females and for HDL3-TG in both males and females.

Our study provides the first RIs for HDL2-C, HDL3-C and HDL3-TG in a Spanish adult population using a single-step precipitation method. The single-step precipitation method proved to be simple, reproducible, cost-effective and suitable for routine clinical laboratory practice in assessing cardiovascular risk.