Why Do Doctors Monitor the Concentrations of LDL & HDL in Patients' Blood?

HDL and LDL carry cholesterol in the blood. They are more important than total cholesterol in estimating heart disease and stroke risks.

HDL and LDL

• HDL is called "good" because it holds on to cholesterol; at high levels, it appears to carry cholesterol back to the liver where the body gets rid of it. LDL is called "bad" cholesterol because it can build up in the arteries.

Target Levels

• The higher the HDL the better. On average, HDL ranges from 40 to 60 mg/dL of blood. HDL levels 60 mg/dL and higher protect against heart disease. LDL levels should be less than 100 mg/dL

Total Cholesterol

• Total cholesterol is computed from HDL and LDL. A high LDL can make total cholesterol high--as can a high HDL level. The person with the higher HDL is healthier, even if her cholesterol is also higher.

Cholesterol Ratio

• To get a better picture of what cholesterol levels mean, doctors divide total cholesterol by a person's HDL. A person who has total cholesterol of 265 with an HDL of 40 has a cholesterol ratio of 6.6-to-1. The American Heart Association recommends a ratio of 5-to-1 or less--ideally, 3.5-to-1.

Significance

• HDL and LDL provide better information about an individual's risk of heart attack or stroke.