Non-invasive assessment of intraluminal lipolysis using a 13CO2 breath test

Techniques available for the study of lipase activity in the gut are unsatisfactory. Breath tests measuring labelled carbon dioxide (13CO2) may provide a useful means for this assessment. Six subjects with cystic fibrosis and pancreatic insufficiency and 10 controls received a test meal containing [13C] trioctanoin, and breath 13CO2 was measured using a dual inlet, dual detector isotope ratio mass spectrometer. Comparison of postprandial breath 13CO2 enrichment allowed complete separation between children with pancreatic insufficiency and controls. Administration of one capsule of pancreatic enzyme with the test meal resulted in an increase in 13CO2 production in all six patients, and four capsules produced a further increase in five of the six. Serial fat balance studies on four of the patients while receiving comparable doses of oral enzyme failed to demonstrate a progressive improvement in fat absorption. The [13C]trioctanoin breath test may prove a safe, non-invasive technique not only for the detection of pancreatic insufficiency, but also for the quantitative study of intraluminal lipolysis.