Test for alcoholic cirrhosis by conversion of [14C]- or [13C]galactose to expired CO2

After ingestion of galactose (10 g per m2) labeled with 14C or 13C, breath was collected from subjects at intervals for 4 hr followed by measurement of 14CO2 by liquid scintillation counting or of 13CO2 by mass spectrometry. Nine subjects without liver disease and 21 "cirrhotic" patients were tested with 14C; 8 control subjects and 4 patients with diagnosis of cirrhosis were tested with 13C. The mean rates of expiration of labeled CO2 by the patients with "cirrhosis" were one-third to one-half of mean normal rates during the first 90 min. The time of peak concentration of tracer CO2 for cirrhotic patients (150 to 180 min) was later than for normal subjects (90 to 120 min). There was distinctly greater separation between control and liver disease groups by test of 14CO2 radioactivity at 1 hr than by serum alkaline phosphatase, total bilirubin, and transaminase, but only slightly better separation than by serum albumin concentration (which was highly correlated with 14CO2 output). The [14C]galactose test is simpler than the standard intravenous galactose tolerance test, and , like the latter, appears superior to some other tests for recognition of cirrhosis. The use of 13C provides an example of a new direction for clinical application of this stable, nonradioactive nuclide.