Exocrine pancreatic insufficiency: Accuracy and clinical value of the uniformly labelled C-13-Hiolein breath test

Background and Aims-The C-13-Hiolein breath test (98% [U-C-13] labelled long chain triglyceride mixture (highly labelled triolein) was evaluated as a non-invasive, non-radioactive test for exocrine insufficiency. Accuracy validity were examined reference to both the secretin pancreozymin test and faecal fat analysis. Methods-A secretin pancreozymin test and faecal fat analysis were performed in 46 patients, 30 with exocrine pancreatic insufficiency and pancreatic function. In all of these patients and in seven healthy volunteers (controls), a C-13-Hiolein breath test was performed using 2 mg/kg [U-C-13] labelled Hiolein with a standard rice snack (1 . 5 g/kg; 25% fat). (CO2)-C-13/(CO2)-C-12 enrichment in the exhaled breath was measured by isotope ratio mass spectrometry. Results-In patients with pancreatic steatorrhoea the (CO2)-C-13 response was below the 95% confidence interval of (CO2)-C-13 exhalation in the controls. These responses were also diminished (p<0 . 001) compared with patients with impaired lipase output but normal fat excretion and with disease as well as healthy controls. There was a linear correlation between stimulated lipase output and the ratio of lipase output/(CO2)-C-13 response (r=0 . 95). Among the 40 patients in whom direct pancreatic function testing was clinically indicated, the sensitivity of the C-13-Hiolein test for detecting steatorrhoea was 91 . 7%, with a specificity of 85 . 7%. Conclusions-In patients with pancreatic disease the C-13-Hiolein breath test reflects impaired lipase output and indicates decompensated lipolysis. The C-13-Hiolein breath test is a convenient alternative to faecal fat analysis.