Cardiovascular disease has become the first cause of death in urban and rural populations in China, and the incidence of ischemic cardiovascular disease (including coronary heart disease and ischemic stroke) based on atherosclerosis is increasing in the modern society with faster economic development. Our cohort studies have shown that elevated total serum cholesterol or LDL cholesterol is one of the independent risk factors for coronary heart disease and ischemic stroke. For this reason, it is crucial to understand the basics of lipids. Lipids are the collective term for plasma cholesterol, triglycerides (TG) and lipids such as phospholipids. The main clinically relevant lipids are cholesterol and TG, in addition to free fatty acids (FFA) and phospholipids. Cholesterol and TG in circulating blood must be bound to specific proteins, namely apolipoproteins (apo), to form lipoproteins that can be transported to tissues for metabolism. Applying ultracentrifugation, plasma lipoproteins can be classified into celiac (CM), very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL), low density lipoprotein (LDL) and high density lipoprotein (HDL). In addition, there is a lipoprotein called lipoprotein (a). Dyslipidemia originally referred to elevated levels of cholesterolC or/and triglycerides (TG) in plasma. In recent years, it has been gradually recognized that decreased plasma high-density lipoprotein cholesterol (HDL-C) is also a disorder of lipid metabolism. As a result, it has been suggested to use dyslipidemia, and it is believed that this name can more comprehensively and accurately reflect the state of dyslipidemia. Dyslipidemia is a relatively common group of diseases, except for a few secondary dyslipidemia due to systemic diseases, and the majority of primary dyslipidemia due to genetic defects or interaction with environmental factors. The basic items are total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), which should be performed for any individual who needs cardiovascular risk evaluation and lipid-lowering drug treatment. Other lipid items such as apoA I, apoB, Lp(a), etc. are research items and are not included in the basic clinical testing items. 1.TC: TC is the sum of cholesterol contained in each lipoprotein in the blood. The main factors affecting TC level are: age and gender: TC level often rises with age, but no longer rises or even declines after the age of 70, and is lower in young and middle-aged women than in men, and TC level is higher in women after menopause than in men of the same age. Dietary habits: long-term high cholesterol, high saturated fatty acid intake can cause TC elevation. Genetic factors: Mutations in enzymes or receptor genes related to lipoprotein metabolism are the main cause of significantly elevated TC. 2, TG: The TG measured clinically is the sum of TG contained in each lipoprotein in plasma. the TG level is also influenced by both genetic and environmental factors. Unlike TC, the TG level of the same individual is more affected by factors such as diet and different time, so the TG value of the same individual may have a large difference when measured several times. 3, HDL-C: Basic research has confirmed that HDL can transport cholesterol from peripheral tissues such as blood vessel walls to the liver for catabolism, suggesting that HDL has anti-atherosclerotic effects. Since HDL contains many components, there is no method to comprehensively detect the amount and function of HDL in clinical practice, so we can indirectly understand the amount of HDL in plasma by detecting the amount of cholesterol it contains. 4, LDL-C: LDL metabolism is relatively simple, and cholesterol accounts for about 50% of the weight of LDL, so it is currently believed that LDL-C concentration basically reflects the total amount of LDL in blood. increased LDL-C is the main lipid risk factor for the occurrence and development of atherosclerosis. In general, LDL-C is parallel to TC, but TC level is also influenced by HDL-C level, so it is better to use LDL-C instead of TC as the risk assessment of coronary heart disease and other atherosclerotic diseases. Fourth, the target of dyslipidemia screening Dyslipidemia and other risk factors for cardiovascular disease are mainly detected through clinical routine work, which is not limited to patients who come to the hospital for cardiovascular disease, but should include all dyslipidemia and cardiovascular disease prone people who come to the hospital. Routine health screening of the general population is also an important way to detect dyslipidemia. For timely detection and detection of dyslipidemia, fasting lipid measurements, including TC, LDL-C, HDL-C and TG measurements, are recommended at least once every 5 years for adults over 20 years of age. For ischemic cardiovascular disease and its high-risk group, lipids should be measured every 3 to 6 months. For patients hospitalized for ischemic cardiovascular disease, lipids should be measured at the time of admission or within 24 h. Key targets for lipid screening: (1) Those who have coronary heart disease, cerebrovascular disease or peripheral atherosclerotic disease. (2) Those with hypertension, diabetes, obesity, and smoking. (3) Those who have a family history of coronary heart disease or atherosclerosis, especially those who have early onset of coronary heart disease or other atherosclerotic diseases in the immediate family. (4) Those who have skin yellow tumor. (5) Those who have a family history of dyslipidemia. It is also recommended that men over 40 years of age and postmenopausal women should have annual lipid screening. If you have dyslipidemia, it is recommended that you go to a regular hospital as soon as possible to receive medical treatment and take effective measures to avoid serious consequences.