Determination of the upper limits of normal serum alanine aminotransferase (ALT) level in healthy Turkish population

Abstract

Background and Aim: Recent studies have reported that the widely ac-cepted range of upper limits of normal (ULN) alanine aminotransferase (ALT) levels (ULN<40U/L) is high for the healthy population. We aimed to find the correct ULN level for men and women in a presumed healthy liver population group. Materials and Methods: The data of 7410 healthy subjects visiting the check-up clinics were retrospectively analysed in this study. Patients were divided in to “healthy liver group” (n=2694) and “high-risk liver group” (n=4716) based on fatty liver on ultrasound, existing of chronic liver dis-ease, ongoing significant alcohol consumption, diabetes mellitus and dys-lipidaemia. Receiver operating characteristic (ROC) curves were generated and the area under the curve (AUC) was calculated at the 95th percentiles for both men and women. Results: The AUC score of ALT for men was 0.92, and the ULN for the serum ALT in men was found as 32.10 U/L (sensitivity of 0.89, specificity 0.85). The AUC score of ALT for women was 0.90, and the ULN for serum ALT was found as 23.15 U/L (sensitivity of 0.90, the specificity of 0.88). Conclusion: ULN for serum ALT level should be lowered and different cut-off values should be used for men (32.10 U/L) and women (23.15 U/L).