Evaluation of triglycerides, total cholesterol and high density lipoprotein-cholesterol stability in human whole blood and plasma samples

Lipid tests are routinely performed in the laboratory for early diagnosis of lipid disorders and prevention of cardiovascular diseases. The aim of this study was to evaluate the stability of triglycerides (TGs), total cholesterol (TC), and high-density lipoprotein-cholesterol (HDL-C) in human whole blood (WB) and plasma samples stored at different temperature conditions in order to improve the quality of lipid testing. This cross-sectional study was conducted at Buon Ma Thuot Medical Testing Center. Ten mL of WB collected from 10 healthy volunteers from 18 to 60 years old were anticoagulated with dipotassium ethylenediaminetetraacetic acid. Five mL of WB were centrifuged to separate plasma. WB and plasma samples were stored at 20°C–25°C and 2°C–8°C. The concentrations of TGs, TC, and HDL-C in WB (WB-TGs, WB-TC, WB-HDL-C) and in plasma samples (P-TGs, P-TC, P-HDL-C) at each time point were determined simultaneously on Erba XL670 system. TGs, TC, and HDL-C were considered stable when the difference between concentrations at the later time point and baseline was not statistically significant. At 20°C–25°C, the concentrations of WB-TGs, WB-TC, P-TGs, and P-TC were stable for less than 4 hours, while the concentrations of WB-HDL-C and P-HDL-C were stable for less than 12 hours. At 2°C–8°C, the concentrations of WB-TGs, WB-TC, WB-HDL-C, and P-HDL-C were stable for up to 48 hours, while the concentrations of P-TGs and P-TC were stable for up to 24 hours. The stability of TGs, TC, and HDL-C in WB and plasma samples was not the same at different temperatures.