An elevated CAm CCr ratio has been used as evidence for the frequent occurrence of acute pancreatitis in the postoperative period. We measured CAm CCr preand postoperatively in 28 patients undergoing extraperitoneal surgical procedures. None of the patients had clinical evidence of pancreatitis, although 2 of the 28 patients had elevated CAm CCr ratios preoperatively. Mean CAm CCr rose from a preoperative level of 2.3 ± 0.3% (1 SE) to 3.2 ± 0.3% on the first postoperative day (P < 0.001). Of the 26 patients with normal preoperative CAm CCr, 12% (3 of 26) developed a clearly abnormal ratio and 12% (3 of 26) developed borderline elevated values. An elevated CAm CCr appears to be a nonspecific postoperative finding and cannot be used as evidence of acute pancreatitis during this period.