Apolipoprotein E (apo E) testing can be used as part of an overall assessment of patient risk for cardiovascular disease (CVD). Apo E can occur in three different forms that can be detected using genetic tests or by examining the proteins contained in a serum sample. Since certain apo E isoforms are associated with increased risk of atherosclerosis, it has been suggested that apo E testing can provide information regarding CVD risk in addition to that provided by the more common lipid tests, such as total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and lowdensity lipoprotein cholesterol (LDL-C). This report does not address the use of the apo E test for those with a diagnosis of diabetes, thyroid disease or renal disease who are at increased risk for CVD.