Clinical efulness of Measurement of Serum Fructosamine in Diabetics: Influence of Renal Failure, Liver Cirrhosis, and Thyroid Dysfunction

Measurement of serum fructosamine (FRA) by means of a Roche kit is a simple and reliable method for estimating glycosylated serum proteins. The level of FRA can be affected by hyperglycemia in diabetics and an abnormal metabolic state of serum proteins such as albumin in patients with renal failure, liver cirrhosis, and thyroid dysfunction. We measured FRA in diabetics and these patients. The average FRA level was 2.58 ± 0.08 (mean ± SE) mmol/l in the normal controls (n=18), 4.60±0.67 in patients with IDDM (n=8), and 3.61±0.10 in patients with NIDDM (n=63). In the patients with non-diabetic renal failure, while the FRA level was significantly (p<0.05) low, FRA corrected by total protein concentration was not different from that of the normal controls. The FRA level in liver cirrhosis without hyperbilirubinemia was not significantly different from that of normal controls. In the patients with thyroid disease, the FRA level was 2.08±0.03 in hyperthyroidism and 3. 11 ±0.07 in hypothyroidism. Moreover, the FRA level was negatively correlated with the thyroid hormones T₃ and T₄ (p<0.001). It is concluded that measurement of FRA is clinically useful for evaluating short-term glycemic control in diabetics even when there is complicating nephropathy or liver cirrhosis. However, its level in diabetic patients with hyperbilirubinemia or thyroid dysfunction must be cautiously interpreted.