A simple new test is described which estimates roughly the proteolytic activity of stools by determining their ability to liquefy gelatin. Fecal suspensions are placed upon gelatin film (unexposed and unfixed) and the extent of removal of the gelatin film noted.
Two groups of patients were studied: (a) 500 normal and sick individuals, and (b) 50 patients with pancreatic fibrosis.
In group (a), less than 5% of the infant group lacked this proteolytic power. As one advanced into the older age groups, this percentage increased. The administration of a laxative to some older children with absent tryptic activity resulted in stools possessing tryptic activity.
A total of 220 separate stool specimens were examined from patients in group (b). In 209 specimens, there was no tryptic activity. The remaining 11 specimens from seven patients showed definite tryptic activity. Three patients in this group had minimal tryptic activity in the duodenal fluid.
When oral pancreatin was given to patients with pancreatic fibrosis, the stools became positive for trypsin. When laxatives were given to a few patients with pancreatic fibrosis, the stool trypsin test remained negative.
The duodenal fluid was assayed in a number of infants with acute and chronic nutritional disturbances, and, when tryptic activity was demonstrated in the duodenal fluid, the stools showed the presence of trypsin.
The possibilities of bacterial or food origin of fecal tryptic activity have been considered and largely eliminated.
Three separate stool examinations by this test in infants are proposed as sufficient either to eliminate or to make probable the diagnosis of pancreatic insufficiency. Conclusions and interpretations based on a single examination is hazardous. At least three menspecimens should be studied and whenever doubt arises duodenal intubation is indicated.