Serum LDL cholesterol is an indicator in blood lipid testing through a blood draw. LDL is a protein synthesized by the liver and is primarily responsible for binding to cholesterol in the blood to form LDL cholesterol, which is transported to peripheral tissues in this form. It is now believed that elevated serum LDL cholesterol, which is directly related to the occurrence of cardiovascular disease, can enter the walls of arteries throughout the body, be engulfed by macrophages, form foam cells, and then increase and fuse together to eventually form atherosclerotic plaques. The ideal level of serum LDL cholesterol for healthy adults should be controlled below 2.6mmol/L, and for patients who have developed cardiovascular disease, it needs to be strictly controlled to a lower level.