[Use of breath analysis in diagnosis of liver function (author's transl)].

Breath tests with analysis of 14CO2 after oral ingestion of 14C-labeled substrates (14C-aminopyrin. 14C-diazepam, 14C-phenacetin, 14C-D-galactose) have been used as quantitative liver function tests. Their diagnostic value is discussed. Breath tests are non-invasive, cheap, easy to perform often without assistance and allow to assess a function of the liver (drug metabolizable function) which is not accessible by other simple analysis techniques. Decreased demethylation of 14C-aminopyrine, 14C-phenacetin, 14C-diazepam is present in chronic liver disease, whereas increased demethylation correlating with chemically determined drug elimination capacity is observed in patients on drugs which induce the capacity of the drug metabolizing enzyme system of the liver.