Cholesterol is a fat-like substance called a lipid that is found in allbody cells. The liver makes all of the cholesterol the body needs to form cell membranes and to make certain hormones. The determination of serum cholesterol is one of the important tools in the diagnosis and classification of lipemia. High blood cholesterol is one of the major risk factors for heart disease. Clinical diagnosis should not be made on a single test result; it should integrate clinical and other laboratory data.