Elevated levels of alanine transaminase and triglycerides within normal limits are associated with fatty liver

In the present study, the threshold values of laboratory data for the diagnosis of non-alcoholic fatty liver disease (NAFLD) were investigated. The study enrolled patients who had undergone abdominal ultrasound (US) between April 2013 and August 2013, and for whom laboratory data were available on the same day. NAFLD was diagnosed following observations of a bright liver or hepatorenal echo contrast on the abdominal US scans. Patients were excluded from the study if they had liver diseases or had been prescribed prednisolone or methotrexate. Receiver operating characteristic curves, the Wilcoxon signed-rank test and Fisher's exact probability test were used for data analysis. In total, 80 NAFLD and 94 non-NAFLD patients were enrolled in the study. The threshold levels of alanine aminotransferase (ALT) and triglyceride (TG) for the diagnosis of NAFLD were 19.0 IU/l and 101 mg/dl, respectively. Patients were divided into two groups according to the levels of ALT and TG. Those with ALT levels of >19 IU/l and TG levels of >101 mg/dl were defined as the positive group, while the remaining patients were classified as the negative group. The specificity and positive predictive value using the combined threshold levels of ALT >19 IU/l and TG >101 mg/dl were 80.9 and 75.0%, respectively. Therefore, the results indicated that ALT levels of >19 IU/l or TG levels of >101 mg/dl were useful markers for the screening of NAFLD. However, NAFLD was more strongly suspected in patients with ALT levels of >19 IU/l and TG levels of >101 mg/dl.