High-density Lipoprotein Cholesterol (HDL-C)

The High-density Lipoprotein Cholesterol (HDL-C) test—also known as HDL cholesterol or alpha-lipoprotein cholesterol—is incorporated into standard lipid panels to help stratify baseline atherosclerotic cardiovascular disease (ASCVD) risk. HDL-C shows an inverse relationship with atherosclerosis; persistently reduced HDL-C, particularly when hypertriglyceridemia is present, is associated with increased cardiovascular risk, while higher HDL-C is relatively protective. Serial HDL-C testing is used to track the effects of dietary modification and lipid-lowering therapy, including strategies intended to raise HDL-C, and to assess progress toward HDL-C and total cholesterol targets.

Cholesterol is a structural sterol produced mainly by the liver and obtained from the diet; it contributes to cell membrane architecture and serves as a precursor for steroid hormones and bile acids. In plasma, it is transported within lipoprotein classes that include very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). HDL particles are protein-rich and carry a smaller proportion of cholesterol. They participate in reverse cholesterol transport by moving surplus cholesterol from peripheral tissues back to the liver for biliary elimination. Higher HDL-C concentrations correlate with less atherosclerotic plaque accumulation, whereas reduced HDL-C—even when total cholesterol is within the normal range—is associated with progression of atherosclerosis.