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AbstractBackground: The clinical usefulness of the ratio of serum aspartate aminotransferase (AST) to alanine aminotransferase (ALT) has been explored in several liver disorders. It has been suggested that in patients with chronic hepatitis C virus (HCV) infection an AST: ALT ≥ 1 has 100% specificity and positive predictive value in distinguishing cirrhotic from non-cirrhotic patients. Such statistical certainty attached to a simple biochemical test merits further evaluation. The present study, therefore, assessed the AST: ALT in patients with chronic HCV infection to determine the validity of the ratio in predicting cirrhosis and to correlate the ratio with the histological grade of necroinflammatory activity and fibrosis. Methods: A retrospective analysis of 153 patients with chronic HCV infection was conducted. Serum biochemistry had been obtained within a mean of 4 weeks of liver biopsy. The histology was scored in terms of activity and fibrosis as described by Scheuer and correlated with AST: ALT. Results: In 30 patients with cirrhosis, the mean AST: ALT (0.99 ± 0.06) was higher than in 123 patients without cirrhosis (0.60 ± 0.02; P < 0.001). A ratio ≥ 1 had 95.9% specificity and 73.7% positive predictive value in distinguishing cirrhotic from non-cirrhotic patients, with a 46.7% sensitivity and 88.1% negative predictive value. The ratio also parallelled the Scheuer score with respect to fibrosis but not with respect to inflammation. Conclusion: Although relatively insensitive, an AST: ALT ≥ 1 is highly specific but not diagnostic for the presence of cirrhosis in patients with chronic HCV infection. The ratio reflects the grade of fibrosis in these patients. [ABSTRACT FROM AUTHOR]

Background and Aim: Fibrotic progression in non-alcoholic fatty liver disease (NAFLD) is associated with impaired hepatic function. The (13) C-caffeine breath test (CBT) is a non-invasive, quantitative test of liver function. We sought to determine the utility of the CBT in detecting hepatic fibrosis in NAFLD., Methods: The CBT was applied to 48 patients with NAFLD. CBT results were compared to clinical, biochemical and histological data. Twenty-four healthy subjects served as controls., Results: Patients with simple steatosis had similar CBT values (2.28 ± 0.71 Δ‰ per 100 mg caffeine) to controls (2.31 ± 0.85, P = 1.0). However, CBT was significantly reduced in patients with non-alcoholic steatohepatitis (1.59 ± 0.65, P = 0.005) and cirrhosis (1.00 ± 0.73, P < 0.001). CBT significantly correlated with Brunt's fibrosis score (r = -0.49, P < 0.001) but not with steatosis (P = 0.23) or inflammation (P = 0.08). CBT also correlated with international normalized ratio (r = -0.61, P < 0.001), albumin (r = 0.37, P = 0.009), aspartate aminotransferase/alanine aminotransferase (r = -0.34, P = 0.018) and platelets (r = 0.31, P = 0.03). On multivariate analysis, age (odds ratio 1.12, 95% confidence interval 1.042-1.203, P = 0.002) and CBT (OR 0.264, 95% CI 0.084-0.822, P = 0.02) were independent predictors of significant fibrosis (F ≥ 2). CBT yielded an area under the receiver operating characteristic curve of 0.86 for the diagnosis of cirrhosis., Conclusions: The CBT reflects the extent of hepatic fibrosis in NAFLD and represents a non-invasive predictor of fibrosis severity in this condition., (© 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd.)