LDL (low-density lipoprotein) cholesterol is "bad" cholesterol, which carries mostly fat and only a small amount of protein from the liver to other parts of the body. A high LDL cholesterol level is considered a risk factor for coronary artery disease (CAD) because, under certain conditions, it can cause hardening of the arteries (atherosclerosis).

Cholesterol is measured either in milligrams per deciliter of blood (mg/dL) or in millimoles per liter of blood (mmol/L).

• An LDL cholesterol level of less than 100 mg/dL (less than 2.6 mmol/L) is considered optimal.
• 100 to 129 (2.6 to 3.35) is considered near optimal.
• 130 to 159 (3.35 to 4.10) is considered borderline high.
• 160 to 189 (4.12 to 4.88) is considered high.
• 190 and above (4.90 and above) is considered very high.

People who have at least a moderate risk for developing heart disease (especially those who have diabetes) may benefit from lowering their LDL cholesterol levels. The specific target LDL level depends on a person's number and type of risk factors.