Advanced glycosylation end products (AGEs) are a potentially useful marker for monitoring glycemic control, predicting the risk of diabetes- and aging-associated clinical complications, and monitoring the treatment of patients with micro- and macrovascular diseases, including retinopathy, atherosclerosis, nephropathy, and neuropathy. AGEs or AGE-proteins are derived from nonenzymatically glycated proteins (Amadori products) after further cross-linking with other proteins and additional rearrangement. AGE-proteins can be assayed by either radioreceptor or immunoassays in blood and tissues. No commercial kit is available at this time.