Low-density lipoprotein cholesterol (LDL-C) levels in plasma/serum are currently used by physicians to identify patients at risk for developing coronary artery disease (CAD) and for the diagnosis and therapeutic management of lipid disorders, particularly hyperlipidemias and dyslipidemias. LDL-C is one of the major risk factors for CAD, and several studies have demonstrated the benefits to patients who lower their LDL-C levels by therapy with statin drugs. It is important to note that not all patients with CAD are identified by LDL-C testing. We will demonstrate that our oxidized LDL/HDL ratio test (the ratio of atherogenicity/anti-atherogenicity) identifies about 50% more patients with clinical evidence of CAD than the LDL-C test. Oxidized LDL is the atherogenic form of LDL-C and is found in atherosclerotic plaques, but not in healthy arteries. We will compare the results of our automated oxidized LDL/HDL ratio test in (1) patients in the general New York patient population; in (2) presumably healthy, elderly Swedish patients without CAD; and (3) in Swedish patients with acute coronary syndrome. We will demonstrate by receiver-operating-characteristic curve (ROC curve) analysis and odds ratios that the oxidized LDL/HDL ratio test has greater diagnostic accuracy in discriminating between healthy control subjects and CAD patients when compared with other currently available lipid/lipoprotein biomarkers. The oxidized LDL/HDL ratio test could become the replacement for the time-honored LDL-C test.