A type of cholesterol (blood fat) transporter that is protective against inflammatory diseases (such as heart disease). HDL is called ‘good cholesterol’ since it can be eliminated from the body carrying away ‘bad (LDL) cholesterol’ with it thus preventing it from building up in arteries (major blood vessels). The ratio of total cholesterol to HDL cholesterol (obtained by dividing the number of each by each other) is an important measurement for predicting artery diseases (such as atherosclerosis) which your doctor can run blood tests for. The goal is to keep the ratio below 5.0, but it’s best below 3.5. HDL measurement on its own should generally be 1.0, but above >1.0 is better if your risk of heart disease is already high (e.g. a previous heart attack or stroke).
See Low Density Lipoprotein (LDL) and Triglycerides.