High levels of high-density lipoprotein, or HDL, cholesterol in the blood can reduce the risk of developing heart disease, states the Centers for Disease Control and Prevention. Monitoring HDL levels helps doctors determine when treatment is needed to lower low-density lipoprotein, or bad cholesterol, levels.
HDL cholesterol is considered good because it helps clear excess LDL cholesterol from the bloodstream, according to WebMD. HDL also regulates LDL levels by carrying these molecules to the liver, where they can be reused instead of replaced. As HDL molecules move through the bloodstream, they clean harmful debris from the inner walls of blood vessels, slowing the arterial narrowing process that typically leads to heart disease.