A variety of liver enzymes assist in diagnosis of alcohol addiction including, gamma-glutamyl transferase (GGT), the most sensitive and widely employed marker, alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Elevated levels of these enzymes may indicate alcoholic hepatitis or cirrhosis; levels do not return to normal once drinking stops.
GGT
According to the journal "Addiction," GGT is one of the longest established biochemical tests for excessive alcohol consumption. GGT is an enzyme in bile, which is induced to rise by alcohol and serum levels due to liver damage, Dr. Subir Kumar states in the Indian Journal of Clinical Biochemistry. It is more likely to be elevated in regular drinkers than binge drinkers.
GGT is limited as a screening tool due to its relatively poor sensitivity. Only 30 to 50 percent of excessive drinkers have elevated levels. GGT tends to be the first test elevated in alcohol-induced liver damage.
ALT
Like GGT, the aminotransferases act not only as markers of alcohol consumption but also as indicators of liver damage from alcohol. ALT is more specific than AST for alcohol-induced liver injury because this enzyme is found predominantly in the liver. The most common cause for ALT elevation is fatty infiltration of the liver, which may or may not be related to alcohol consumption.
AST
AST is less specific than ALT, because it is found in several organs, including the liver, heart, muscle, kidney and brain. Very high levels of aminotransferases may indicate alcoholic liver disease. Clinicians often use a patient's AST to ALT ratio of greater than two to confirm an impression of heavy alcohol consumption. According to the Journal Digestive Diseases and Sciences, when aminotransferases are elevated and the AST:ALT ratio is greater than two, it is highly suggestive that it is due to alcohol.
References
- "Addiction"; Traditional markers of excessive alcohol use; Dr. Katherine M. Conigrave; Dec 2003
- "Indian Journal of Clinical Biochemistry"; Biochemical Markers For Alcohol Consumption; Dr. Subir Kumar Das; 2003
- "Digestive Diseases and Sciences"; The SGOT/SGPT ratio-an indicator of alcoholic liver disease
