At a Glance
Why Get Tested?
To determine risk of developing heart disease
When to Get Tested?
A blood sample drawn from a vein in the arm or from a fingerstick
Test Preparation Needed?
If this test is to be performed as part of a complete lipid profile, fasting for 9-12 hours will be required; only water is permitted.
The Test Sample
What is being tested?
High-density lipoprotein (HDL cholesterol, HDL-C) is one of the classes of lipoproteins that carry cholesterol in the blood. HDL-C consists primarily of protein with a small amount of cholesterol. It is considered to be beneficial because it removes excess cholesterol from tissues and carries it to the liver for disposal. Hence, HDL cholesterol is often termed “good” cholesterol. The test for HDL cholesterol measures the amount of HDL-C in blood.
High levels of cholesterol have been shown to be associated with the development of hardening of the arteries (atherosclerosis) and heart disease. When cholesterol levels in the blood increase (not enough is removed by HDL), it may be deposited on the walls of blood vessels. These deposits, termed plaques, can build up, causing vessel walls to become more rigid, and may eventually narrow the openings of blood vessels, constricting the flow of blood.
Higher levels of blood HDL-C can decrease your risk of developing plaques by removing excess cholesterol from your blood.
How is the sample collected for testing?
The test for HDL-C uses a blood sample. Most often, the blood sample is collected from a vein. Sometimes HDL-C is measured using a drop of blood collected by puncturing the skin on a finger. A fingerstick sample is typically used when HDL-C is being measured on a portable testing device - for example, at a health fair.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
Since this test is usually performed as part of a complete lipid profile, fasting for 9-12 hours may be required with only water permitted.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
National Heart, Lung, 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 July 2008.
Pagana K, Pagana T. Mosby's Manual of Diagnostic and Laboratory Tests. 3rd Edition, St. Louis: Mosby Elsevier; 2006. pp 351-355.
MayoClinic.com. Cholesterol Levels, What numbers should you aim for? (June 21, 2008). Available online at http://www.mayoclinic.com/health/cholesterol-levels/CL00001 through http://www.mayoclinic.com. Accessed July 2008.
American Heart Association. What Your Cholesterol Level Means. (April 7, 2008). Available online at http://22.214.171.124/presenter.jhtml?identifier=183#HDL through http://126.96.36.199. Accessed July 2008.
Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC. Pp252-253.
Ken-ichi Hirano, et al. Atherosclerotic Disease in Marked Hyperalphalipoproteinemia: Combined Reduction of Cholesteryl Ester Transfer Protein and Hepatic Triglyceride Lipase. Arteriosclerosis, Thrombosis, and Vascular Biology. 1995;15:1849-1856. Available online at http://atvb.ahajournals.org/cgi/content/full/atvbaha;15/11/1849?eaf through http://atvb.ahajournals.org. Accessed May 2010.
MedWire News: Dangerous edge to very high HDL-C levels. J Am Coll Cardiol 2008; 51: 634-642. Available online at http://www.lipidsonline.org/news/article.cfm?aid=5936 through http://www.lipidsonline.org. Accessed May 2010.
Lia Tremblay (LifeWire). Are High HDL Levels the Answer to Cholesterol Problems? Why High HDL Levels May Not Be Good Enough. Available online at http://cholesterol.about.com/lw/Health-Medicine/Conditions-and-diseases/Is-Increasing-HDL-Levels-the-Answer-to-Cholesterol-Problems-.htm through http://cholesterol.about.com. Accessed May 2010.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.
American Heart Association. "What are healthy levels of cholesterol?" Article available online at http://188.8.131.52/presenter.jhtml?identifier=183