Revising the upper limit of normal for levels of serum alanine aminotransferase in a middle eastern population with normal liver histology

Background: Recently, the upper limits of normal (ULN) for alanine-aminotransferase (ALT) has been recommended to be lowered to ≤30 U/l in men and ≤19 U/l in women. Aim: To evaluate the ALT concentrations in a healthy Middle Eastern population with biopsy-proven normal liver tissue. Methods: ALT values were calculated from 175 consecutive Saudi potential living liver donors who underwent a liver biopsy as part of a stepwise pretransplant workup. Results: The mean age of the 110 potential donors with normal liver histology was 27 ± 6.2 years for men and 38.6 ± 7.1 years for women. The mean body mass index (BMI) levels were 23.0 ± 3.5 kg/m ² for men and 24.7 ± 3.25 kg/m² for women, and the ALT levels were higher in male patients (22.6 ± 9 vs. 16.4 U/l ± 8, p value = 0.003). Multivariate linear regression showed that BMI and sex were independent variables that were positively associated with the levels of ALT (p < 0.0001). Moreover, when we analyzed donors according to the Prati criteria, 63 (36.0 %) of the individuals were classified into this subgroup. The mean ALT concentration was 12.9 U/l ± 4.5 in women and 19.7 U/l ± 6.9 in men, and these values were significantly lower than those obtained from subjects who did not fit the Prati criteria (19.4 U/l ± 1.8, p = 0.04 for women and 29.0 U/l ± 12.1, p = <0.0001 for men). Thus, we calculated healthy ALT values of 33 IU/l for men and 22 IU/l for women. Conclusions: The ULN for ALT levels in Middle Eastern populations should be lowered, including separate values for males and females. Furthermore, metabolic parameters were shown to have a significant effect on ALT levels.