Serum radioactivity of 14C-triolein and 3H-oleic acid ingested in a test meal:a rapid test of pancreatic exocrine insufficiency.

A double-tracer technique to estimate lipid digestion was investigated. 3H-labelled oleic acid and 14C-labelled triolein were ingested in a test meal. The serum radioactivity of 3H after ingestion of labelled oleic acid depends on absorption and metabolism of free fatty acids, while serum radioactivity of 14C from triolein, in addition to the former, depends on triglycerol digestion. This study shows that the ratio between 3H and 14C 2h after the test meal gives a good qualitative and quantitative estimation of lipid digestion: the 3H/14C ratio in patients with maldigestion is significantly higher than for normals (P less than 0.01), the predictive value of the 3H/14C ratio in the diagnosis of maldigestion is high, that of a positive result being 1.0 and that of a negative 0.93, and quantitatively the 3H/14C ratio shows a highly significant correlation with faecal fat (P less than 0.001). The test is very easy to perform, lasts for only 2 h, and is without discomfort to the patient or nursing and laboratory staff. It gives information like or superior to that of faecal fat measurement.