Alanine Transaminase (ALT) levels in normal adult Sri Lankans

Abstract

BACKGROUND : Alanine transaminase (ALT) levels are widely used in screening for liver disease.The upper limit of normal (ULN) of ALT (males 30 IU/l, females 19 IU/l) have been definedfor western populations. Normal levels have not been established for Asian populations. OBJECTIVES: To establish levels of ALT for a normal, adult Sri Lankan population METHODS: This study was part of a community based investigation - Ragama Health Study (RHS). The study population consisted of 35-64 year old adults, selected using stratified random sampling. Consenting adults were screened by a structured interview, liver ultrasound and collection of 10 ml venous blood. The “normal” population was defined as those not using potentially hepatotoxic drugs, safe alcohol consumption (14 units/week for males, 7 units/week for females), absence of fatty liver, and being HBsAg and anti-HCVab negative. ALT levels were estimated by a kit using the Bergmeyer method. The 95th percentile of the ALT levels was taken as the ULN. RESULTS: 3012 subjects participated in the study. The ALT level (U/l) among 831 normal males (mean 36, median 30, SD 20, ULN 68) was significantly higher than that of the 885 normal females (mean 29, median 25, SD 13, ULN 53) (p<0.001,Student's t-test ). CONCLUSION: The ULN for ALT levels of a “normal” Sri Lankan population was higher than observed in western populations. The levels were higher in males. ULN for ALT may need to be redefined for different population groups.