Fructosamine--an underutilized tool in diabetes management: case report and literature review

Glucose binds irreversibly to a variety of structures, including hemoglobin and proteins, by non-enzymatic glycosylation. Glycosylated Hemoglobin A1c (HbA1c) measures the blood glucose control over the lifespan of the RBCs. The importance of routinely assessing HbA1c in diabetic patients is well established. Both individual and institutional performance in the diabetes arena may be judged by the number of patients reaching target HbA1c values. In some patients, however, the HbA1c does not accurately portray glycemic control and may delay treatment for poorly-controlled diabetes. We report on a patient in whom the HbA1c values were falsely low as a result of hemolytic anemia associated with Myelodysplastic syndrome. The patient had consistent elevation of glucose values. Fructosamine measurement was able to confirm poorly-controlled diabetes and assist in improving diabetes control. Fructosamine is unaffected by disorders of red blood cells, which have a profound potential influence on HbA1c. Fructosamine also has the advantage of accurately reflecting shorter-term changes in glycemia that correspond to the half-life of albumin. In diabetic patients with HbA1c values below the lower limit of normal, a routine Fructosamine level should be performed. We recommend a Fructosamine level should be considered in all patients with red blood cell disorders or with discrepancies between glucose measurements and HbAlc values. Fructosamine, an inexpensive assay, is currently underused in the clinical practice. A guideline for using Fructosamine levels is included and some of the pitfalls in relying solely on the HbAlc are discussed.