Since high density lipoproteins (HDL) fractions contain albumin when determined from serum by conventional precipitation methods, phospholipids in HDL do not demonstrate the accurate level of HDL-phospholipids. In the present study, true phospholipid levels in HDL were estimated using high performance liquid chromatography (HPLC), and the levels were compared with the phospholipids in HDL determined by the precipitation method. Serum from 18 healthy subjects was tested. Under the HPLC method, after extracting HDL fraction, subfractions of HDL were separated by monitoring cholesterol and phospholipids. It was found that phospholipids in the albumin fraction contained 20.2±1.6% (mean±S.D.) of the total HDL-phospholipids. Albumin-phospholipids correlated inversely with HDL2-phospholipids (r=-0.472, p<0.05), and with HDL2-cholesterol (r=-0.507, p<0.05). No correlation was observed between serum total phospholipids and albuminphospholipids. A significant correlation was observed between HDL-phospholipids determined by the precipitation method and HDL fraction phospholipids determined by the HPLC (r=0.903, p<0.001). These results suggest that HDL-phospholipids determined by the precipitation method gives useful clinical data.
