What is the normal serum alanine aminotransferase (ALT) value for Thai subjects with the low risk of liver diseases?

Abstract

Background : It still remains unclear whether the currently used normal range for serum alanine aminotransferase (ALT) levels really reflects a healthy liver.

Objective : To determine the thresholds for healthy ALT values or the normal value for Thai subjects with the low risk of liver diseases who participate in the annual physical checkup at King Chulalongkorn Memorial Hospital (KCMH).

Materials and Methods : We retrospectively reviewed the medical records of annual health examination, including questionnaires conducted at KCMH, Thailand from January to December 2006. A group of the low risk of liver diseases was selected by excluding patients who showed any abnormalities of the risk factors that were significantly associated with the serum ALT level, including hepatitis B, hepatitis C, alcohol consumption, diabetes, hyperlipidemia and obesity.

Results : The mean age of the 1,879 enrolled subjects was 41.7 ± 10.1 years, and 81.7% of them were female. The upper limit range of the ALT level of the group of subjects with the low risk of liver diseases (i.e. 95th percentile) was 33.6 IU/L for males and 32 IU/L for females. The upper thresholds of AST and ALT value of the subjects with the metabolic syndrome (METS) were statistically significantly higher than those in subjects without METS (AST 57.4 vs. 30IU/L and ALT 87.3 vs. 31.6 IU/L).

Conclusion : The ALT threshold of the group of Thai subjects with the low risk of liver diseases was clearly lower than the previously accepted threshold (<40IU/L). Metabolic syndrome significantly affects the ALT threshold level.