Serum fructosamine concentration in patients with nephrotic syndrome and with cirrhosis of the liver: the influence of hypoalbuminaemia and hypergammaglobulinaemia.

We have investigated the influence of variation of the concentrations of serum albumin and immunoglobulins on serum fructosamine concentration in 33 patients with nephrotic syndrome, and 18 patients with cirrhosis of the liver. Protein alterations were evident in these patients and they were compared with 109 normal subjects, 43 patients with type II diabetes mellitus and nine diabetic patients with nephrotic syndrome. The mean serum fructosamine concentration in diabetic patients (2.76 +/- 0.53 mmol/L) was significantly increased (P less than 0.001) by comparison with normal subjects (1.93 +/- 0.20 mmol/L) and the other patients studied. Patients with diabetic nephropathy had higher (P less than 0.01) serum fructosamine concentrations (2.23 +/- 0.54 mmol/L) than non-diabetic patients with the nephrotic syndrome (1.57 +/- 0.37 mmol/L) but remained with the normal range. Positive correlations were observed between fructosamine and immunoglobulins G and M in nephrotic and cirrhotic patients. Serum immunoglobulin A was also directly correlated with serum fructosamine in patients with cirrhosis of the liver. An inverse correlation between albumin and fructosamine in serum of patients with cirrhosis of the liver was also noted. We conclude that the fructosamine assay is not useful in the assessment of glycemic control in patients with cirrhosis of the liver, nephrotic syndrome or in any other clinical situation in which protein metabolism is altered.