13C-Methacetin Breath Testing in Patients with Non-Alcoholic Fatty Liver Disease

Background. Non-alcoholic fatty liver disease (NAFLD) is a very common chronic liver condition which may potentially develop into fibrosis and cirrhosis. Liver biopsy is still the gold standard for liver fibrosis detection in these patients. However, non-invasive tools for liver assessment in NAFLD patients, like the C-13-methacetin breath test, may be useful. Objectives. The aim of the study was to evaluate the utility of the C-13-methacetin breath test in NAFLD patients, especially in predicting significant fibrosis. Material and Methods. Thirty three patients (24 male and 9 female (average age 47.9)) with histologically proven NAFLD had the C-13-methacetin breath test performed. Results. Different forms of NAFLD were found during the histology phase, from simple steatosis to advanced fibrosis. Simple steatosis (SS) was found in 18 subjects (54.5%), in another 15 (45.5%) signs of inflammation and fibrosis (NASH) were observed. However, more than half of the patients with liver fibrosis had only minimal changes described (0/1). The sensitivity of the test was highest for cumulative recovery after 10 min of the test and for a combination of two parameters (the cumulative recovery after 40 min and the time of maximal momentary recovery). The positive predictive value was low for all the parameters under consideration, but the negative predictive value was over 0.8 in significant fibrosis detection. Conclusions. The C-13-methacetin breath test could be a promising noninvasive tool for excluding at least F1 fibrosis in NAFLD patients.