Determination of High-Density Lipoprotein Cholesterol by Heparin-Ca<sup>++</sup> Precipitation and Enzymatic Measurement

Abstract

A simple and precise HDL-cholesterol estimation method using precipitation procedure with heparin and Ca++ was descrived.To 0.1ml of serum was added 2.0ml precipitation reagent containing 50ml/dl of heparin and 25mM of CaCl2. Samples were mixed throughly and allowed to stand at 4°C for 20mim before centrifugation at 4°C and 1, 500 G for 15mim. Cholesterol in the supernate was measured by enzymatic method.Separation of HDL was examined on the Ouchterlony double diffusion method. A precipitation reaction with anti α-lipiprotein (HDL) antibodies was found only in the supernte and anti β-lipoprotein (LDL plus VLDL) line only in the precipitate.The precision of the present method appeared excellent (CV, 0.90-1.2%). A regression anlysis of the data obtained using ourmethod (Y) compared to ultracentrifugation method (X): Y=1.017X+0.72(mg/dl), and r=0.986The heparin-Ca++ precipitation method seams feasible in the routine clinical laboratory use.