[Urinary proteins in patients with diabetes mellitus]

In the second morning urine of 51 patients with diabetes mellitus (type I/II) albumin, N-acetyl-beta-D-glucosaminidase (NAG), alpha 1-microglobulin (alpha 1-M/U), creatinine (reference parameter) as well as serum alpha 1-microglobulin and creatine were determined. Following an international expert recommendation, three groups were formed depending on albumin excretion: group 1: albumin less than 24 mg/g creatinine (normal range) group 2: albumin greater than 24 mg/g creatinine and less than 200 mg/g creatinine (so called microalbuminuria) group 3: albumin greater than 200 mg/g creatinine (manifest proteinuria) The urinary tubular parameters NAG and alpha 1-microglobulin were above normal range in 17 and 21% respectively in group 1. For group 2 the results were abnormal in 94 and 69% and for group 3 in 100% of patients. Albuminuria correlated with NAG activity, but not with alpha 1-microglobulin excretion. These results indicate, that measuring NAG and alpha 1-microglobulin as markers for tubular dysfunction can give additional diagnostic informations about type and degree of diabetic nephropathy.