[Labelled CO2 breath-tests in gastroenterology (author's transl)]

The use of a few microcuries of 14C labelled molecules with very short biological half-life for breath-tests gives no more body irradiation than 10 minutes' exposure to the sun. Yet it provides the gastroenterologist with accurate information. Detection and identification of fat malabsorption are easy when 3 labelled lipids are used. Glycine 1 14C cholate administered orally offers a simple, rapid and effective screening technique for the detection of increased bile salt deconjugation and may provide a valuable diagnostic supplement in the study of steatorrhea after ileal resection, bypass or bacterial overgrowth. The clearance of labelled aminopyrine can be decreased in hepatocellular dysfunction or increased in some alcoholic patients or in patients receiving phenobarbitone. Tracer doses of labelled ethanol were used to study the metabolism of ethanol by the liver in alcoholic patients. Chronic ingestion of alcohol stimulates the activity of microsomal drug-metabolising enzymes in both non-cirrhotic and cirrhotic patients; this response is lost in acute liver damage and in chronic alcoholic disease with severe hepatic dysfunction. The CO2-labelled breath-tests are non-invasive, effective and inexpensive. The forthcoming replacement of 14C by non-radioactive 13C or briefly radioactive 11C will render these tests even more attractive.