Cholesterol is a steroid with a secondary hydroxyl group in the C3 position, and found in blood, bile, and brain tissue. It serves as a precursor to bile acids, steroids and vitamin D. It is synthesized in many types of tissue, but particularly in the liver and intestinal wall. Approximately, 75% of cholesterol is newly synthesized and a 25% originates from dietary intake.

Measurements of serum cholesterol levels are important in the diagnosis and classification of hyperlipoproteinemias. Elevated cholesterol levels may occur with hypothyroidism, nephrotic syndrome, diabetes, and various liver diseases. There is a correlation between elevated serum cholesterol levels and the incidence of coronary artery diseases. Normal cholesterol levels are affected by stress, diet, age, gender, hormonal balance, and pregnancy. Depressed levels are associated with hyperthyroidism and severe liver diseases1, 2.