After pancreatic transplantation bladder drainage is preferred over enteric drainage for the better monitoring of which levels?

Major advantage of bladder drainage after pancreatic transplant is the ability to monitor the patient for graft rejection. Decrease of more than 50% in urine amylase activity after pancreas transplantation signals possible acute rejection. The decrease in urinary amylase may be the only clinical indication of a problem, with no change in the serum concentration of creatinine or glucose or activity of serum amylase or lipase. Biopsy of pancreas is done to confirm diagnosis of rejection. Ref: Stem Cell Therapy for Diabetes By Shimon Efrat, Page 71