Glycated albumin: An old yet new biomarker in people with diabetes and the potential for novel applications

Glycated albumin (GA), the product of nonenzymatic glycation of serum albumin, reflects the mean glucose levels over the preceding approximately 2 weeks, bridging the gap between daily self-monitoring of blood glucose and the roughly 3-month window covered by glycated hemoglobin (HbA1c) measurement. First quantified in the early 1980s, GA was long overshadowed by HbA1c, but at present, interest has revived for two reasons. First, HbA1c assessment proves unreliable when the erythrocyte lifespan or hemoglobin glycation is perturbed, as in patients with renal failure, hemolytic anemia, hemoglobin variants, and iron deficiency. Second, continuous glucose monitoring has drawn attention to postprandial excursions and shortterm glucose variability that are not captured by HbA1c. This review revisits GA's biology, measurement, standardization, clinical utility, limitations, and evidence linking it to diabetic complications. Because it responds within 2 weeks to treatment and is markedly influenced by postprandial glucose excursions, GA supports early monitoring of therapy, and its ratio to HbA1c serves as an index of postprandial glycemia and insulin secretion. However, it must also be recognized that conditions that alter albumin turnover change GA levels independently of blood glucose levels. The prognostic value of GA is strongest in patients on maintenance hemodialysis, although recent studies in various cohorts and a meta-analysis have expanded situations in which GA measurement is of prognostic value. New measurement approaches, including finger-prick sampling, weekly home measurement, and noninvasive saliva and tear assays, point toward a renewed role for GA measurement in everyday glucose monitoring in individuals with diabetes.