Definition:
HDL stands for high-density lipoprotein. It's also sometimes called "good" cholesterol. Lipoproteins are made of fat and protein. They carry cholesterol, triglycerides, and other fats, called lipids, in the blood to various parts of the body. This article discusses the blood test used to measure the level of HDL cholesterol in your blood. See also:
Alternative Names:
High-density lipoprotein test
How the test is performed:
A blood sample is needed. Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood. Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
How to prepare for the test:
You may be told not to eat or drink anything for 9 - 12 hours before the test. The health care provider may tell you to stop taking certain drugs before the procedure.
How the test will feel:
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performed:
This test is done to check the level of cholesterol in your blood and to see if you are at high risk for a heart attack, stroke, or other cardiovascular problem. Studies of both men and women have shown that the higher your HDL, the lower your risk of coronary artery disease. This is why HDL is sometimes referred to as "good" cholesterol. The main function of HDL is to help soak up excess cholesterol from the walls of blood vessels and carry it to the liver, where it breaks down and is removed from the body in the bile. The laboratory test for HDL actually measures how much cholesterol is in each high-density lipoprotein particle, not the actual amount of HDL in the blood.
References:
Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III guidelines. Circulation. 2004 Jul 13; 110(2):227-39. Semenkovich CF. Disorders of lipid metabolism. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 217.
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