Alternate Names : High-Density Lipoprotein, Good Cholesterol
An HDL test measures the level of high-density lipoprotein, or HDL, in the blood. HDL is known as the good carrier for cholesterol. Cholesterol is a waxy substance that is used for many body processes. The HDL test is generally done along with a total cholesterol and LDL test.
The HDL test is usually done as part of a lipid profile test that also includes total cholesterol, LDL, and triglycerides.
Who is a candidate for the procedure?
An HDL test may be ordered to evaluate a person's risk for various conditions. Adults 20 years or over should be tested every five years for cholesterol, LDL, HDL, and triglycerides. Low HDL levels increase a person's risk for the following:
arteriosclerosis, or narrowing of the arteries
coronary heart disease, or CHD
early death from heart disease
An HDL test may also be ordered to evaluate disorders of the kidney, liver, or thyroid gland.
How is the test performed?
A blood sample needs to be taken to measure the level of blood cholesterol. The blood is usually drawn from a vein in the forearm or the hand. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube called a tourniquet is wrapped around the upper arm. This enlarges the veins in the lower arm by restricting blood flow through them. A very thin needle is gently inserted into a vein and the tourniquet is removed. Blood flows from the vein through the needle and is collected in a syringe or vial. The sample is sent to the lab to be analyzed. After the needle is withdrawn, the puncture site is covered for a short time to prevent bleeding.