Measurement of duodenal tryptic activity and 75Se-selenomethionine pancreatic scanning compared as tests of pancreatic function.

The results of a subjective assessment of pancreatic function, based on the appearance of a (75)Se-pancreatic scan, were compared with measurements of the tryptic activity of duodenal aspirates in 16 normal and 38 abnormal subjects. In normals and in abnormals whose scans showed a generalized rather than a localized abnormality there was close agreement between the results of the two sets. In patients with a localized abnormality of the pancreatic head on scanning the tryptic activity of the aspirate was useful in differentiating carcinoma of the pancreas from that of the common bile duct. In general the scan was the more discriminative test though otherwise the places of the two tests in diagnosis are rather similar. The particular situations in which each test is valuable, or in which one or other test can be omitted, are discussed.