Correlation Between Albumin Concentration, N-acetyl-β-D-glucosamidase and β2-microglobulin in Urine in Insulin-Dependent Diabetic Children Without Persistent Microalbuminuria

First morning urine (FMU), out-patient urine (OPU) and 24-hours urine (24HU) were collected in thirty-two insulin dependent diabetic children without persistent microalbuminuria aged 5 to 18 years, and urinary N-acetyl-β-D-glucosaminidase (NAG), β_2-microglobulin (β_2-MG) and urinary albumin concentration (UAC) were measured and studied the associations between NAG, β_2-MG, UAC, urine glucose concentration (UG), age, diabetic duration and hemoglobin-A_1c. NAG were elevated in 6 patients (21%) in FMU, 4 patients (13%) in OPU. β_2- MG were elevated in 1 patient (3%) in FMU, 3 patients (9%) in OPU. UAC were elevated over 20 μg/ml in 6 patients (21%), in FMU, 6 patients (19%) in OPU. Significantly positive correlations were observed between NAG and UAC in FMU, OPU and 24HU, between NAG and UG in 24HU, and between UAC/creatinine ratio in FMU and hemoglobin A_1c. These data suggest that subclinical renal tubular injury could occur frequently and could disturb the reabsorption of UAC in diabetic children without overt nephropathy, and also suggest that urine glucose could play a major role in the injury