Urinary N-acetyl-beta-glucosaminidase in children with acute renal failure

Urinary excretion of N-acetyl-beta-glucosaminidase (NAG) was measured in random urine as the ratio of NAG to grams of urinary creatinine. Sixteen children with acute renal failure as well as 8 patients without serum creatinine changes after ischemic insults or nephrotoxic hazards were evaluated for their urinary NAG excretion. For children without renal failure, there was a significant increase (p less than 0.001) in urinary NAG after insults. The urinary NAG returned to normal within 2 weeks. In children with acute renal failure, the mean peak serum creatinine was 3.6 +/- 2.0 mg/dl, and the mean duration between onset and the time serum creatinine returning to normal was 8.8 +/- 4.1 days. Urinary NAG was markedly elevated during acute azotemic stage, remained at high level (p greater than 0.05) after serum creatinine returning to normal, and even continued to be abnormal several weeks after clinical recovery. Corrected with age, the mean urinary NAG level was elevated 6 times above normal after insults in patients without renal failure, and 34 times greater than normal in children with acute renal failure (p less than 0.01). We suggest that the extent of elevation of urinary NAG may be used to monitor the development of acute renal failure in patients exposed to potentially nephrotoxic hazards.