Glycated Hemoglobin and Serum Proteins as Tools for Monitoring

Abstract Technological advances have greatly improved our ability to monitor glycemic control in patients with diabetes. To this end, one of the most important clinical advances that has improved modern diabetes care is the recognition that glucose undergoes nonenzymatic chemical reactions with various proteins in the blood, including hemoglobin, in a manner that allows the estimation of an integrated value of the glucose excursions over a period of weeks to months, providing a useful window for glucose monitoring using the hemoglobin A1c(HbA1c). The early 1980s also saw the emergence of a second group of tests, collectively called “fructosamine,” which were based on a determination of glycated serum proteins, especially albumin, and found to be useful for similar clinical purposes over a shorter time period (2–3 weeks) compared to the HbA1c. There has also been growing interest in utilizing measurement of advanced glycosylation end products (AGEs) in serum and in tissues as laboratory correlates of some of the chronic tissue damage observed in patients with diabetes. In the present chapter, starting from a chemical description of the glycation reactions, we will present the pathophysiological background necessary for an understanding of the variety of tests now used for glycated hemoglobin and albumin determination and their interpretation in different clinical encounters. Finally, we will describe AGEs and their potential relationship to the chronic complications of diabetes.