HDL stands for high-density lipoprotein. It is also known as good cholesterol. Other types of lipoprotein include low-density lipoprotein (LDL) known as bad cholesterol and very-low-density lipoprotein (VLDL). HDL is the smallest type of lipoproteins and it is synthesized and secreted by the liver and small intestine. HDL functions as a scavenger. It carries the bad cholesterol (LDL) from the blood back to the liver where the bad cholesterol is broken down and excreted from the body. Low HDL cholesterol levels can be caused by risk factors such as uncontrolled diabetes, smoking, sedentary lifestyle, fatty diet, alcohol consumption, obesity and genetic factors. Having low HDL cholesterol levels increases the risk of cardiovascular disease, atherosclerosis and stroke. Hence, it is important to maintain good levels of HDL cholesterol in the blood. Simple investigations such as blood lipid profile can detect the levels of good and bad cholesterol in the blood.