Cholesterol efflux capacity of High-Density Lipoprotein (HDL) is a new biomarker that characterizes a key step in reverse cholesterol transport. Excessive cholesterol in the cell is either converted to cholesteryl esters (CE) or effluxed out of the cell by a number of intracellular transporters, such as ABCA1, ABCG1 and SR-BI. The natural acceptor of cholesterol in serum is HDL and ApoAI. A strong negative correlation exists between cholesterol efflux capacity of serum and atherosclerosis. BioIntersect’s Cholesterol Efflux Assay (Cat # 5000) is designed to quantitate the rate of cholesterol efflux from cultured cells and/or the capacity of plasma/serum acceptors to accept cholesterol released from the cells. The assay is validated macrophage J774, Endothelial, HepG2, RAW, differentiated THP- 1 and adipocyte cells.