13C-methacetin and 13C-galactose breath tests can assess restricted liver function even in early stages of primary biliary cirrhosis

Objective. The ¹³C-methacetin breath test quantitatively evaluates cytochrome P450-dependent liver function. The ¹³C-galactose breath test non-invasively measures the galactose oxidation capacity of the liver. The aim of this study was to find out whether these breath tests are sensitive parameters also in non-cirrhotic patients with primary biliary cirrhosis.

Material and methods. Nineteen patients with early-stage primary biliary cirrhosis (no cirrhotic alterations in the liver biopsy, Ludwig stage I–III) and 20 healthy controls underwent the ¹³C-methacetin and ¹³C-galactose breath tests.

Results. Patients with primary biliary cirrhosis metabolized less ¹³C-methacetin than controls (cumulative recovery within 30 min 7.5±2.4% versus 14.0±2.6%; p<0.001). When a cut-off?>?9.8% was used for the cumulative recovery after 30 min, the methacetin breath test reached 84.2% sensitivity and 95.0 specificity. In the ¹³C-galactose breath test, the percentage recovery at 60 min in patients was 3.1±1.3%/h, and 6.3±1.1%/h in controls (p<0.001). Using a cut-off?>?4.7%/h, the galactose breath test reached 89.5% sensitivity and 95.0 specificity.

Conclusions. In non-cirrhotic, early-stage, primary biliary cirrhosis the ¹³C-methacetin breath test and the ¹³C-galactose breath test reliably indicate decreased liver function. The ¹³C-galactose breath test can also predict the histological score.