Cholesterol is used to build up cells, protect nerves, create hormones and many other vital functions in your body. As a type of lipid, or fat, cholesterol cannot move through your bloodstream freely. Often cholesterol is bundled together with special compounds called lipoproteins, FamilyDoctor.org explains. These lipoproteins can pick up cholesterol and transport it within the blood to other cells in the body. Measuring the amount and type of lipoproteins in the blood can help determine the amount of cholesterol and fat you have circulating in your bloodstream.
HDL
High-density lipoprotein, or HDL, is often termed "good cholesterol" because high HDL levels often indicate a reduced risk of disease, the American Heart Association reports. HDL can remove excess cholesterol from the arteries and help prevent the build up of atherosclerotic plaques or blood clots. HDL typically makes up one-third to one-fourth of all the blood lipoproteins and helps transport excess cholesterol out of the blood vessels. Ideally, HDL levels should be above 60 mg/dL and low HDL levels, less than 40 in males and 50 in females, often leads to an increased risk of heart disease.
LDL
LDL, or low-density lipoprotein, is a form of "bad cholesterol" that can cause damage to your blood vessels. The majority of the lipoproteins in your blood are LDL molecules. LDL's main function is delivering cholesterol to the blood and other parts of the body. Elevated levels of LDL result in the formation of plaques, atherosclerosis and an increased risk of heart disease and stroke. Excess LDL in the blood can become oxidized, enter the walls of your arteries and then cause the formation of plaques that block blood flow.
VLDL
A less well-known type of lipoprotein is VLDL, or very-low-density lipoprotein. VLDL is usually not reported on a routine cholesterol test, as it is difficult to directly measure this chemical, MayoClinic.com says. VLDL molecules contain the highest amount of triglyceride, or fat molecules. Therefore, VLDL is often used to measure fat levels within your blood. High VLDL levels, and thus high triglyceride levels, often correlate with an elevated risk of coronary artery disease. A normal VLDL level ranges from 5 to 40 mg/dL.
Elevated Cholesterol
Abnormally high cholesterol tests often indicate that you have a greater chance of suffering from heart disease, stroke or other cardiovascular conditions. Normally, you would want your total cholesterol level, which is the sum of HDL, LDL and other cholesterol carrying compounds, to be lower than 200 mg/dL. If your total cholesterol is high and either your LDL or VLDL levels are elevated, then you may be at risk of serious complications, FamilyDoctor.org warns. However, an increased total cholesterol due to a high HDL level usually does not indicate an increased risk of developing heart disease.
