A blood sample drawn from a vein in your arm or a fingerstick
Usually fasting for 9-12 hours before the test (only water permitted) and no alcohol for 24 hours before the test; follow any instructions you are given.
Very low-density lipoprotein (VLDL) 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.
At present there is no simple, direct way of measuring VLDL cholesterol. 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. This estimate is used in most settings. The calculation is not valid, however, when the triglyceride level is greater than 400 mg/dl (4.5 mmol/L) because other lipoproteins are usually present. Triglycerides testing most often requires that the patient fast before sample collection; otherwise these calculations may be invalid.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm. Sometimes a drop of blood is collected by puncturing the skin on a fingertip.
Is any test preparation needed to ensure the quality of the sample?
Since VLDL-C is usually calculated from the triglyceride level, preparation is the same as for the triglyceride test. Current recommendations for this testing include fasting (having nothing to eat or drink except water) for 9 to 12 hours beforehand and avoiding alcohol consumption for at least 24 hours before the test. Follow any instructions you are given.
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?
What does the test result mean?
An elevated level of VLDL cholesterol (>30 mg/dL or >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 the choice of therapy used to lower a person's cholesterol, such as lifestyle changes or drug treatment.
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 health care provider about what is right for you.