Low GGT enzyme activity does not indicate a problem, in which case there is no liver or bile duct damage in the body.
However, elevated GGT enzyme activity indicates liver damage, the higher its level, the greater the degree of damage. The increase may be due to liver disease, viral infection (Hepatitis B, Hepatitis C), some environmental damage (solvent, adhesive), drugs that cause liver damage (e.g. non-steroidal anti-inflammatory drugs, oral contraceptives, antidepressants), alcoholism, disease of the pancreas, congestive heart failure or hyperthyroidism. In case of women, enzyme levels may increase with age.