Patterns of N-acetyl-beta-D-glucosaminidase excretion after renal transplantation.

N-Acetyl-beta-D-glucosaminidase activity (NAG) was assayed in 750 early morning urine samples from 25 renal transplant patients during the post operative period. Eighty four per cent of all acute rejection episodes were preceded or accompanied by a greater than two-fold rise in NAG activity; similar increases were caused by dialysis, gentamicin therapy and ureteric dehiscence. Only 9% of all significant increases in NAG excretion could not be accounted for by any of these four processes. Analysis of the day-to-day pattern of NAG activity as opposed to individual NAG values provided a clue to the occurrence of rejection during immediate post-transplantation oliguria.