A 13-year-old spayed Doberman Pinscher with acute vomiting of 24 hours' duration and concurrent 2-week history of polyphagia with weight loss had diabetic ketoacidosis complicated by acute pancreatitis and exocrine pancreatic insufficiency. Diagnostic testing for exocrine pancreatic insufficiency, by determining serum trypsin-like immunoreactivity, revealed an unexpectedly high result when a low result was anticipated. High trypsin-like immunoreactivity was attributed to acute pancreatic inflammation.