[Fructosamine values in hyperthyroidism, hypothyroidism and gammopathy]

Fructosamine values in two groups of hypo- and hyperthyroid patients were compared with the values in a reference group of non-diabetics. In hyperthyroid patients the fructosamine values were significantly lower than in the reference group. Also the mean concentrations of albumin and total protein in serum are significantly lower for hyperthyroid patients compared to hypothyroid patients. The results do not provide evidence for a simple relationship between fructosamine and protein values in these patient groups. Therefore we do not recommend to relate fructosamine to protein or albumin using correction factors. Under conditions of thyrotoxicosis fructosamine is no reliable indicator of previous serum glucose concentrations. The test is not affected by monoclonal IgG gammopathy.