Free Paper Session : Liver 1 ; Should The Upper Limit Of Normal For Serum Alanine Aminotransferase Level Be Revised? = Free Paper Session : Liver 1 ; Should The Upper Limit Of Normal For Serum Alanine Aminotransferase Level Be Revised?

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Background/Aims: Serum alanine aminotransferase (ALT) activity, reflecting the degree of hepatic necroinflammation, is one of the most frequently measured liver tests in persons who are suspected to have liver disease. But current upper limit of normal (ULN) of ALT, 40 IU/L, often can not detect the subclinical liver disease with minimal to mild inflammation. We, therefore, evaluated the ULN of ALT of healthy adult subjects in order to assess the necessity of revision for currently accepted reference range of ALT. Methods: 23,898 adult subjects who visited for medical examination at Health Promotion Center, Dankook University Hospital, from January 2005 to December 2006, were retrospectively enrolled in the present study. We excluded the adults who had HBsAg, anti-HCV, anti-HIV, VDRL, history of current medication and alcohol consumption more than 40 g/week, and high risks for liver disease defined as BMI more than 23 kg/m2, serum cholesterol level more than 240 mg/dL, triglyceride more than 200 mg/dL, fasting glucose more than 115 mg/dL, and ultrasonographic liver diseases including fatty change. We defined updated ULN of ALT as activity below 95th percentile for each gender. Results: 5,994 adults (2,983 men, 2,961 women) met the inclusion criteria of this present study. Updated ULN of ALT levels were 38 IU/L in men and 25 IU/L in women. This ALT activity showed a tendency to increase according to age increase, and revealed positive correlation with the ultrasonographic degree of fatty liver. Serum ALT activity below 95th percentile of HBsAg or anti-HCV positive carrier subjects, whose medical conditions were equal to those of enrolled healthy subjects in aspect of biochemical and ultrasonographic finding, were 75 IU/L and 77 IU/L, respectively. Conclusions: Updated ULN of ALT was lower than currently accepted ALT activity. Considering age and gender, current reference range of serum ALT level should be revised for the detection of subclinical liver diseases such as fatty liver.