Detection of postoperative pancreatitis after pancreatic surgery by urine trypsinogen strip test

The urine trypsinogen strip test has been used successfully in the diagnosis of pancreatitis of various aetiologies, but has not been studied in postoperative pancreatitis. The aim of this study was to evaluate this test for the diagnosis of postoperative pancreatitis after pancreatic resection.

Fifty patients undergoing pancreatic resection were included. The urine trypsinogen strip test was done daily during the first postoperative week, blood was analysed before and 4, 6 and 10 days after surgery, and amylase activity in the drainage fluid was measured on days 4 and 6. Patients underwent computed tomography (CT) before operation and on days 2 and 6 afterwards.

Thirteen patients (26 per cent) developed CT-detected pancreatitis after operation. In 12 of these patients pancreatitis was detected on the second postoperative day. The urine trypsinogen test was positive in all 13 patients with postoperative pancreatitis, and was already positive on the first day after surgery in 12. The sensitivity, specificity, and positive and negative predictive values of the trypsinogen strip test in detection of postoperative pancreatitis were 100, 92, 81 and 100 per cent respectively. In receiver-operator characteristic analysis the area under the curve (AUC) was higher for the urine trypsinogen strip test (AUC 0.959) than for a serum amylase level more than two (AUC 0.731) or three times (AUC 0.654) above the upper normal range in the diagnosis of postoperative pancreatitis. Patients whose recovery was complicated by pancreatic fistula, detected by drain output measurements on day 6, more often had a positive urine trypsinogen test than patients without a fistula (11 of 12 versus five of 38; P < 0.001).

This study suggests that the urine trypsinogen strip test might be a valuable method for diagnosis of pancreatitis after pancreatic surgery.