Small, dense, low-density lipoprotein and atherosclerosis.

Disorders of low-density lipoprotein (LDL) and high- density lipoprotein (HDL) subclass distribution are more common contributors to coronary artery disease (CAD) than is elevated low-density lipoprotein cholesterol (LDLC). Recent research has emphasized the importance of LDL and HDL subclass distribution in patient management and response to treatments. Laboratory determination of LDL and HDL subclass distribution involves analytic ultracentrifugation or polyacrylalmide gradient gel electrophoresis. If subclass distribution is to be used for patient management, research quality control and standards are necessary in order to assure that the patient's values accurately reflect the metabolic disorder. The importance of this topic for patient care has been recognized by the medical insurance industry. Investigations employing electron beam computed tomography in asymptomatic individuals has revealed that 50% with established CAD have normal lipids by National Cholesterol Education Program (NCEP) criteria. However, a large proportion of other metabolic contributors to CAD are not revealed by routine blood tests.