Comparative determinations of low-density-lipoprotein-cholesterol

Abstract

Two different methods for low-density-lipoprotein-cholesterol (LDL-C) determination were comparatively used. The heparin-sodium citrate (pH 5.12) precipitation method gave similar LDL-C results to the ones given by the Friedewald et al. formula (3.2 vs 3.3 mmol/l) in 187 men. Values obtained using both methods show a very high and significant correlation (r > 0.9; p < 0.001). However, LDL-C values obtained with the precipitation method were 15% higher in hypertriglyceridemics (triglycerides (Tg) > or = 2.3 mmol/l). A paired-comparison between data obtained by both methods indicates a clear serum Tg-values influence, because LDL-C values obtained by the precipitation method were significantly more frequently higher (p < 0.05 or p < 0.01) than LDL-C values obtained using the Friedewald's formula in hypertriglyceridemic men (Tg > or = 1.7 mmol/l or Tg > or = 2.3 mmol/l respectively). When a 3.9 mmol/l LDL-C level break was chosen, Friedewald's formula gave 13% false hypercholesterolemics. The influence of Tg was again significant in men with both, hypercholesterolemia and hypertriglyceridemia, while LDL-C values obtained by the precipitation method were significantly more frequently higher (p < 0.01).