Carcinoma of prostate
Carcinoma of breast and lung
Systemic lupus erythematosus
Congestive heart failure and chronic coronary artery disease: The level of elevation correlates with the risk of death secondary to cardiovascular disease.
GGT levels may be increased due to medications, such as carbamazepine, cimetidine, furosemide, heparin, isotretinoin, methotrexate, oral contraceptives, phenobarbital, phenytoin, and valproic acid.