Fructosamines are formed by the nonenzymatic addition of glucose to proteins other than hemoglobin. These reactions form ketoamines; glycated albumin is the primary fructosamine.
Fructosamine is not ordinarily measured clinically. However, when abnormal hemoglobins or rapid hemoglobin turnover is present, the glycated hemoglobin assay may not be accurate and a fructosamine assay is recommended for evaluation of long-term diabetic control.
The half-life for albumin is approximately 20 days. The concentration of glycated albumin is an index of glucose control over a period of 2 to 3 weeks. When earlier detection of carbohydrate management changes is needed, fructosamine would detect changes earlier than Hb A1C.