HDL is an acronym for High-Denisty Lipoprotein. HDL's main function is to carry cholesterol from other parts of the body back to the liver where it is eliminated from the body. HDL is considered the "good" cholesterol because higher levels are associated with decreased risk for heart disease.

Serum Blood Cholesterol Test

A physician will have a patient undergo a serum blood cholesterol test so that the differing levels of the various types of cholesterol may be measured. Cholesterol is measured in the blood as milligrams of cholesterol per decaliter of blood. Therefore, a level for HDL of 47 would mean there is 47 mg of HDL per decaliter of blood. This convention is shortened to 47 mg/dl.

HDL Cholesterol

Levels below 40 are considered to be a high risk factor for heart disease. High levels of HDL are considered a negative risk factor for heart disease. A negative risk factor means that it helps prevent heart disease.

LDL Cholesterol

LDL is the main cholesterol component physician's look at when determining heart disease risk and a treatment plan. LDL levels over 130 mg/dl is considered high. Below 130 mg/dl is considered to be good and levels below 100 mg/dl are considered to be optimal.

Total Cholesterol

Total cholesterol is the level of circulating blood cholesterol made up of all the differing fractional components such as LDL and HDL. While the NHLBI institute still considers total cholesterol levels of 200 mg/dl or below to be optimal, the total number does not separate out the "good" HDL from the "bad" LDL. This lack of specificity is why health care providers prefer to separate out the different fractions to get a better grasp of heart disease risk.

Heart Disease Risk Factors

There are many different risk factors for heart disease. Cholesterol is one component of this risk factor stratification. High LDL (bad) levels and low HDL (good) levels are definite risk factors for heart disease. While having high LDL and low HDL levels does not guarantee a person will develop heart disease, it does raise the chances that it will occur.


If someone does have a negative cholesterol profile, such as low HDL, there are various options that a person may try. To reduce the chances of disease development, a lifestyle geared towards heart health should be adopted. If these strategies are not enough, an individual's physician may want to try cholesterol altering medication in addition to lifestyle changes.