Comparability of two different polyacrylamide gel electrophoresis methods for the classification of LDL pattern type

Background: The measurement of small dense low-density lipoprotein (sdLDL) particles is relevant when assessing cardiovascular risk. However, there is as yet no referenced method for the determination of LDL subfractions or a standardized comparison of the methods currently available. Therefore, the aim of this study was to compare the pattern of LDL particles measured by polyacrylamide tube gel electrophoresis (PTGE) and polyacrylamide gradient gel electrophoresis (PGGE) and to correlate the results with triglyceride concentration. Materials and methods: Serum samples were collected from 177 patients. Lipid profile and LDL particle size were assessed using PTGE and PGGE. Results: Pearson correlation and kappa index revealed a very good agreement between the methods. There was 81.3% concordance for classification of sdLDL particles and 97.2% concordance for classification of large LDL when PTGE and PGGE were compared. LDL size correlated with triglyceride in subjects with triglyceride levels >116 mg/dl, pointing to a high CAD risk, as reflected by their higher prevalence of pattern B. Conclusions: PTGE correlates favourably and is in very good agreement with PGGE. The determination of LDL particle size may be an appropriate analytical procedure to estimate CAD risk in patients with high triglyceride levels. (C) 2011 Elsevier B.V. All rights reserved.