Normal blood lipids for a 45 year old person: total cholesterol <5.20mmol/L, LDL ≤3.4mmol/L. Lipids are serum lipids, including cholesterol, triglycerides, phospholipids and free fatty acids. Lipids can be used as a diagnostic indicator for lipid metabolism disorders and related diseases. Normal values for blood lipids are: total cholesterol <5.20mmol/L, triglycerides <1.70mmol/L, HDL >1.0mmol/L, LDL ≤3.4mmol/L. The blood lipids of serum lipids include triglycerides (TG), phospholipids and free fatty acids. Triglycerides (TG) and low-density lipoproteins (LDL) are closely related to the development of diseases such as atherosclerosis. Increased TG may be seen in coronary artery disease, primary hyperlipidemia, and atherosclerosis, while decreased TG may be seen in severe liver disease and malabsorption. Increased LDL can determine the risk of coronary heart disease (positive correlation, the higher the LDL, the higher the risk of atherosclerosis), nephrotic syndrome. decreased LDL is seen in hyperthyroidism, malabsorption, cirrhosis.