Immunoreactive serum trypsin in diseases of the pancreas

Immunoreactive serum trypsin was measured with a double antibody radioimmunoassay in normal subjects and patients with various diseases of the pancreas. The normal range is 115-350 ng/ml with a geometric mean of 212 ng/ml. No trypsin was found in serum after total duodenopancreatectomy, in about 75% of patients with cystic fibrosis and in a few patients with pancreas carcinoma or chronic pancreatitis. Reduced serum trypsin levels between 10 and 100 ng/ml were measured in the remaining 25% of cystic fibrosis and in one third of the patients with chronic pancreatitis. Serum trypsin was increased to 700-17,000 ng/ml in all patients with acute pancreatitis or during the acute phase of chronic pancreatitis. Absent or reduced serum trypsin is a reliable indicator of total or partial exocrine pancreatic insufficiency whereas considerably increased serum trypsin concentration do indicate acute pancreatitis.