At a Glance
Why Get Tested?
To help assess the risk of developing heart disease
When to Get Tested?
When other lipid tests, such as a lipid profile, are being performed
A blood sample drawn from a vein in your arm or a fingerstick
Test Preparation Needed?
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.
The Test Sample
What is being tested?
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.
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Sources Used in Current Review
MayoClinic.com. VLDL cholesterol: Is it harmful? Available online at http://www.mayoclinic.com/health/vldl-cholesterol/AN01335 through http://www.mayoclinic.com. Accessed September 2013.
MedlinePlus Medical Encyclopedia. VLDL test. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003494.htm. Accessed September 2013.
Sources Used in Previous Reviews
MedlinePlus Medical Encyclopedia: VLDL Test. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003494.htm. Accessed May 2010.
National Heart, Lung and Blood Institute. National Cholesterol Education Program Guidelines, Cholesterol, ATP III. Pp 31-34. PDF available for download at http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3full.pdf through http://www.nhlbi.nih.gov. Accessed May 2010.
OhioHealthOnline. VLDL cholesterol: What is it? Available online at http://www.ohiohealth.com/bodymayo.cfm?xyzpdqabc=0&id=6&action=detail&ref=2755 through http://www.ohiohealth.com. Accessed May 2010.