From the Guidelines
In patients with suspected alcoholic liver disease, an AST level of 293 IU/L is suggestive of alcoholic hepatitis, but levels above 500 IU/L should prompt consideration of other etiologies 1. The diagnosis of alcoholic liver disease (ALD) is made by documenting alcohol excess and evidence of liver disease, with no single laboratory marker definitively establishing alcohol as the etiology of liver disease 1.
- Key laboratory abnormalities in ALD include elevated serum aminotransferases, with AST typically elevated to a level of 2-6 times the upper limits of normal in severe alcoholic hepatitis 1.
- An AST/ALT ratio higher than 2 is seen in about 70% of patients with ALD, but this may be more valuable in patients without cirrhosis, and ratios greater than 3 are highly suggestive of ALD 1.
- However, AST levels above 500 IU/L or ALT levels above 200 IU/L are uncommon in alcoholic hepatitis and should suggest another etiology, such as concomitant acetaminophen overdose or other liver injuries 1.
- Therefore, an AST level of 293 IU/L, while elevated, is still within the range typically seen in alcoholic hepatitis, and further evaluation and consideration of other etiologies is not immediately necessary based on this value alone 1.
From the Research
AST Levels in Various Studies
- The study 2 found that after 1 year of UDCA therapy, AST levels were significantly lower in C-AIH patients compared to CHC patients.
- In the study 3, UDCA treatment resulted in a significant reduction of AST levels by 25% from baseline values in patients with chronic hepatitis.
- The study 4 reported a significant decrease in mean serum AST levels in patients with nonalcoholic steatohepatitis treated with a combination of UDCA and vitamin E.
- A systematic review 5 found that bile acid use, including UDCA, was associated with improved normalization of liver biochemistry, including AST levels, in non-alcoholic fatty liver disease, autoimmune hepatitis, and hepatitis B and C infections.
Effect of UDCA on AST Levels
- UDCA therapy has been shown to reduce AST levels in various liver diseases, including autoimmune-associated chronic hepatitis C 2, chronic hepatitis 3, and nonalcoholic steatohepatitis 4.
- The reduction in AST levels suggests that UDCA may have a beneficial effect on liver function in these diseases.
- However, the study 5 noted that normalization of liver biochemistry, including AST levels, did not always correlate with improvement in histologic disease.