C-13-egg white breath test: a non-invasive test of pancreatic trypsin activity in the small intestine

Background-The recent availability of egg white protein highly enriched wit h C-13 has allowed breath test technology to be adapted for the study of pr otein digestion and absorption. Pancreatic trypsin is considered to be the key enzyme in the proteolytic cascade. Aim-To evaluate trypsin activity in the small intestine of healthy voluntee rs and patients with pancreatic disease by a recently developed C-13-egg wh ite breath test. Methods-A total of 48 healthy volunteers and 30 patients with pancreatic di sease were studied after ingestion of a test meal consisting of 22 g C-13-l abelled egg protein. Breath samples were taken before and after ingestion o f the meal and analysed for (CO2)-C-13 concentration. Moreover, pancreatic trypsin output after maximal stimulation was measured in 13 patients and ni ne healthy volunteers. Results-The six hour cumulative (CO2)-C-13 excretion in breath was signific antly lower in patients than controls (mean (SEM): 6.23 (0.82)% v 19.16 (0. 58)%, p<0.0001). An excellent correlation was found between the six hour cu mulative (CO2)-C-13 excretion and trypsin activity after maximal pancreatic stimulation. Conclusion-The non-invasive C-13-egg white breath test is promising as an i ndirect pancreatic proteolytic function test.