To help assess the risk of developing heart disease
As part of a lipid profile during a regular medical exam (at least once every 4-6 years for adults; for children, at least once between the ages of 9 and 11 and again between the ages of 17 and 21); more frequently if you have risk factors for heart disease
A blood sample drawn from a vein in your arm or a fingerstick
Current standards recommend that testing be done when you are fasting. For 9 to 12 hours before the test, only water is permitted. In addition, alcohol should not be consumed for 24 hours just before the test. Your healthcare practitioner may decide that you may be tested without fasting. Follow any instructions you are given and tell the person drawing your blood whether or not you have fasted.
Very low-density lipoprotein (VLDL, VLDL-C) is one of the four major lipoprotein particles. The other three are high-density lipoprotein (HDL), low-density lipoprotein (LDL), and chylomicrons. Each particle contains a mixture of cholesterol, triglyceride, and protein, but in varying amounts unique to each type of particle. LDL contains the highest amount of cholesterol. HDL contains the highest amount of protein. VLDL and chylomicrons contain the highest amount of triglyceride.
VLDL particles are released into the blood by the liver and circulate in the bloodstream, ultimately being converted into LDL as they lose triglyceride, having carried it to other parts of the body. According to the National Heart, Lung and Blood Institute's National Cholesterol Education Program Guidelines ATP III, there is growing evidence that VLDL plays an important role in atherogenesis, in which plaques form on the interior walls of arteries, narrowing these passageways and restricting blood flow, which can lead to heart disease and increase the risk of stroke.
Currently, direct measurement of VLDL cholesterol requires specialized testing. However, since VLDL-C contains most of the circulating triglyceride (if a person is fasting) and since the composition of the different particles is relatively constant, it is possible to estimate the amount of VLDL-C based on the triglyceride value. To estimate VLDL-C, divide the triglyceride value by 5 if the value is in mg/dL or divide by 2.2 if the value is in mmol/L. In most cases, this formula provides a good estimate of VLDL-C.
However, this formula becomes less accurate with increased triglyceride levels when, for example, a person has not fasted before having blood drawn. The calculation is not valid when the triglyceride level is greater than 400 mg/dl (4.5 mmol/L) because other lipoproteins are usually present. In this situation, VLDL-C may be measured directly using specialized testing.
- How is it used?
Very low-density lipoprotein cholesterol (VLDL-C) may be reported as part of a lipid profile, a group of tests that are often ordered together to determine risk of coronary heart disease and an important part of cardiac risk assessments.
Increased levels of VLDL-C are thought to reflect the presence of particles called lipoprotein remnants that are intermediate particles on the pathway of conversion of VLDL to LDL. When high levels of VLDL are present, the conversion of VLDL to LDL is slowed and the accumulation of intermediate particles is thought to contribute to the development of atherosclerosis and coronary heart disease.
- When is it ordered?
VLDL-C is generally not ordered as a separate test. It may be reported with the results of a lipid profile when a healthcare practitioner wants to determine a person's risk of heart disease.
Lipid profiles are recommended every 4-6 years to evaluate risk of heart disease in healthy adults. Children should have a lipid profile screening at least once between the ages of 9 and 11 and once again between the ages of 17 and 21.
Testing may be ordered more frequently to monitor treatment in people who have identified risk factors for heart disease. Risk factors include a family history of heart disease or health problems such as diabetes, high blood pressure, or being overweight.
- What does the test result mean?
An elevated level of VLDL cholesterol (greater than 30 mg/dL or greater than 0.77 mmol/L), like elevated LDL cholesterol, is considered a risk factor for heart disease and stroke. The presence of high VLDL in addition to high LDL may affect treatment decisions.
Low levels of VLDL cholesterol are not generally a concern.
- Is there anything else I should know?
VLDL cholesterol concentrations, like all lipoprotein fractions, can be measured directly using techniques such as lipoprotein electrophoresis and ultracentrifugation. However, these techniques are complex and expensive and are not usually done in clinical laboratories. These tests are generally carried out in specialty laboratories, most often for research purposes.
- How can I lower my VLDL-C level?
Because of the relationship between VLDL and triglycerides, you can lower your VLDL cholesterol level by taking steps to lower your triglyceride level. These include making healthy lifestyle changes, such as losing excess weight and exercising regularly. It has also been advised to avoid sugary foods and alcohol in particular since these have a strong effect on triglycerides. Cholesterol-lowering medication may also be recommended. Talk to your healthcare provider about what is right for you.