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

BACKGROUND AND AIMS The 13C-Hiolein breath test (98% [U-13C] labelled long chain triglyceride mixture (highly labelled triolein) was evaluated as a non-invasive, non-radioactive test for exocrine pancreatic insufficiency. Accuracy and clinical validity were examined with 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 16 with normal pancreatic function. In all of these patients and in seven healthy volunteers (controls), a 13C-Hiolein breath test was performed using 2 mg/kg [U-13C] labelled Hiolein with a standard risk snack (1.5 g/kg; 25% fat). 13CO2/12CO2 enrichment in the exhaled breath was measured by isotope ratio mass spectrometry. RESULTS In patients with pancreatic steatorrhoea the 13CO2 response was below the 95% confidence interval of 13CO2 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/13CO2 response (r = 0.95). Among the 40 patients in whom direct pancreatic function testing was clinically indicated, the sensitivity of the 13C-Hiolein test for detecting steatorrhoea was 91.7%, with a specificity of 85.7%. CONCLUSIONS In patients with pancreatic disease the 13C-Hiolein breath test reflects impaired lipase output and indicates decompensated lipolysis. The 13C-Hiolein breath test is a convenient alternative to faecal fat analysis.