Serum ALT Levels in a Cohort of Healthy Blood Donors and Volunteers from Saudi Arabia: The Influence of Sex and Body Mass Index

Introduction

Alanine aminotransferase (ALT) is the most sensitive biomarker for hepatocellular injury. It is found in the hepatic cytosol, and its concentration in extrahepatic tissue is low compared to serum aspartate aminotransferase (AST). Normal serum ALT in a selected population varies according to age, sex, and ethnic origin. Similar to other biochemical parameters, the normal level of serum ALT was determined in the 1950s and was then adjusted by biochemical laboratories based on testing the healthy population of both sexes. In Saudi Arabia, the normal biochemical marker levels were last revised by testing university students in 1982. In 2002, Prati et al. in a study from Italy defined new normal levels for serum ALT in a healthy population by testing 6835 healthy blood donors, but these results have only been widely accepted over the past few years. In that study the serum ALT level was found to be directly related to sex and body mass index (BMI). No similar data are available among Saudis. Similar to other parts of the world, obesity and metabolic syndromes are increasingly recog nized among Saudis and other Asians.–() On the other hand, chronic viral hepatitis B and C are highly endemic in this part of the world. Because persistently elevated ALT warrants additional workup for liver disease,) a more precise definition of normal ALT levels may be needed not only to recognize liver injury but also to avoid unnecessary medical testing and treatment in healthy individuals. Genetic differences among Saudis are also expected to influence serum ALT levels and other biochemical markers. In this study, we tested healthy Saudi and Asian blood donors and volunteers to define the normal serum ALT level in comparison to upper limit of normal local reference laboratory values. In addition, we evaluated the effects of sex, BMI, age, and ABO blood group on the serum ALT levels.

Abstract

Serum alanine aminotransferase (ALT) is the most sensitive biochemical marker of hepatocellular injury. The internationally accepted normal level for ALT is 30 U/L in males and 19 U/L in females. Body mass index (BMI) and sex have a significant influence on the ALT levels.

Keywords

Serum ALT, obesity, sex, Body mass index, blood donors, blood group