1 Determination of HDL-Cholesterol They are a good type of cholesterol containing 52% protein , 28%phospholipids and 20% cholesterol . All lipoproteins transfer lipids from cell to cell except HDL-C remove cholesterol from the cells to the liver and change it to bile acids therefore called scavenger . HDL is a major circulating lipoprotein in a beta lipoproteinemia patients . It is produced in the liver and intestine , it travels in the blood stream picking up cholesterol and the cholesterol to other lipoproteins to transport it back to the liver . There are two types of HDL-C :- HDL2 ⟹ M.Wt = 375 K.Dalton HDL3 ⟹ M.Wt = 200 K.Dalton The removing of cholesterol by HDL result from enzymatic activity for Lecithin Cholesterol Acyl Transference (LCAT) by converted of free cholesterol cholesterol ester . Principle :- All methods depends on :- 1-Isolation of HDL 2-Determination of cholesterol by HDL isolation . One of the important methods to isolate HDL is precipitation with polyanions solution . This method depend on ability of precipitate reagents to precipitate all lipoprotein except HDL , such as (Heparin - Manganese chloride , Dextrin sulphate – Magnesium chloride – Sodium phospho tungstate and poly ethylene glycol).