Serum Alanine Aminotransferase as an Annual Screening Tool for Diseases Among Workers

Background and purpose: The objective of this study was to assess the performance of serum alanine aminotransferase (ALT) as an annual screening tool for liver diseases in the occupational medical surveillance of asymptomatic workers. Methods: We collected periodic medical surveillance data in the most recent four years from 700 employees of an oil-refinery. Of these, 326 voluntarily participated in the study and received a complete physical examination including hepatitis B surface antigen (HBsAg), hepatitis C antibody, and abdominal sonogram. The sensitivity and specificity of serum ALT for detecting liver diseases were established, and receiver operating characteristic (ROC) curve analysis was used to clarify the overall value of this test. Results: Serum ALT had low sensitivity (below 45%) and high specificity (above 80%) in detecting liver diseases. There was no shoulder point or clear cut-off value on the ROC curve. Overall, serum ALT was better at detecting fatty liver and hepatitis virus C infection. However, serum ALT failed to detect both fatty liver disease and hepatic fibrosis in the HBsAg (+) subgroup. Obese workers had a higher risk of liver disease (OR 4.4; 95% CI 2.6-7.2), which was mainly due to fatty liver (OR 6.8; 95% CI 4.0-11.7). Conclusions: Serum ALT is not a sensitive screening test for liver disease. We recommend an algorithmic approach to the management of workers that is based upon HBsAg, serum ALT value, and obesity. It involves testing for HbsAg prior to serum ALT in workers from high endemic areas.