Laboratory detection of the early stages of diabetic nephropathy.

Three laboratory indicators of impaired renal function (microalbuminuria (MA), N-acetyl-beta-glucosaminidase (NAG), beta-2-microglobulinaemia (beta-2-M)) were studied in sixty diabetics of type 1. 10 times higher MA levels were found in a subgroup of diabetics with identifiable diabetic retinopathy (DR). In a subgroup of diabetics with normal values of excreted albumin the mean MA value was significantly higher than in those who had already contracted DR. Pathological levels of NAG and beta-2-M were mostly seen in those patients who also had pathological MA results. In only four cases were increased NAG or beta-2-M values as the first and only pathological parameter indicative of possible renal involvement due to diabetic nephropathy.