LDL-cholesterol

To know your LDL level, you must have a fasting lipid profile (also called lipoprotein profile). This is a detailed blood test for cholesterol where you don't eat for 9-12 hours prior to the test. The test determines your LDL levels, as well as total cholesterol, HDL, and triglyceride levels.

LDL stands for Low-Density Lipoproteins. A "lipoprotein" is a mixture of fatty cholesterol and protein. LDL is composed mainly of cholesterol and has very little protein. LDLs are bad because they deposit cholesterol on the walls of your arteries. High LDL levels increase the risk for heart disease.

Source: http://ssmhealth.adam.com/