Cholesterol Test
Alternate Names : Lipid Test, Lipoprotein Test, Total Cholesterol
Definition A cholesterol test measures the amount of cholesterol and triglycerides in serum (part of the blood).
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Why is the Test Performed?
This test is often performed to evaluate risks for heart disease.
Cholesterol is an important normal body constituent, used in the structure of cell membranes, synthesis of bile acids, and synthesis of steroid hormones. Since cholesterol is water insoluble, most serum (the noncellular portion of blood) cholesterol is carried by lipoproteins (chylomicrons, VLDL, LDL, and HDL).
The term "LDL" usually refers to LDL-cholesterol and "HDL" means HDL-cholesterol. The term "cholesterol" usually means total cholesterol (VLDL + LDL + HDL). However, total cholesterol measurements are not used as much these days to determine risk for heart disease.
Chylomicrons are lipoproteins that are present shortly after a meal but disappear within about 2 hours in "normal" individuals.
Triglycerides are another component commonly measured in a lipid or cholesterol test. Triglycerides are compounds used by the body to move fatty acids (formed when fats or oils are consumed) through the blood. These fatty acids may be used by the body for energy or stored (as fat) for later use.
Excess cholesterol in the blood has been correlated with cardiovascular disease. High triglycerides are now associated with heart disease as well. LDL is sometimes referred to as "bad" cholesterol, because elevated levels of LDL correlate most directly with coronary heart disease.
HDL is sometimes referred to as "good" cholesterol since high levels of HDL reduce risk for coronary heart disease. This is because one of the main functions of HDL is to take excess cholesterol to the liver for excretion in the bile. In fact, a high HDL (defined below) will take away one risk factor you may have for coronary disease.
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