From the Guidelines
Elevated gamma-glutamyl transferase (GGT) levels can be caused by various liver and biliary tract diseases, as well as other conditions, including alcoholic liver disease, non-alcoholic fatty liver disease (NAFLD), viral hepatitis, biliary obstruction, cholangitis, primary biliary cholangitis, and primary sclerosing cholangitis, as supported by recent studies 1.
Causes of Elevated GGT
The most common causes of elevated GGT include:
- Alcoholic liver disease
- Non-alcoholic fatty liver disease (NAFLD)
- Viral hepatitis (types A, B, C, D, and E)
- Biliary obstruction (such as gallstones, tumors, or strictures)
- Cholangitis
- Primary biliary cholangitis
- Primary sclerosing cholangitis Medications can also elevate GGT, particularly anticonvulsants (phenytoin, carbamazepine), certain antibiotics, and statins 1. Other conditions associated with elevated GGT include pancreatitis, heart failure, diabetes mellitus, obesity, and certain cancers (especially those affecting the liver, pancreas, or biliary system) 1.
Importance of GGT in Diagnosis
GGT is an enzyme primarily found in liver, bile duct, and kidney cells, and its elevation typically indicates damage to these tissues or enzyme induction. GGT is particularly sensitive to alcohol consumption, often rising before other liver enzymes, making it a useful marker for detecting alcohol-related liver damage 1. However, since GGT can be elevated in many conditions, additional testing is usually needed to determine the specific cause.
Clinical Considerations
In clinical practice, it is essential to consider the patient's clinical history, medications, and other laboratory results when interpreting elevated GGT levels. A comprehensive diagnostic approach, including imaging tests and liver function tests, may be necessary to determine the underlying cause of elevated GGT 1.
From the Research
Diseases Associated with Elevated GGT
Elevated Gamma-Glutamyl Transferase (GGT) levels are associated with various diseases, including:
- Liver diseases such as primary biliary cholangitis (PBC), drug-induced liver injury (DILI), alcoholic liver disease (ALD), and non-alcoholic fatty liver disease (NAFLD) 2
- Cardiovascular disease, as elevated GGT is linked to increased risk of cardiovascular events and mortality 3, 4
- Type 2 diabetes, as high normal serum GGT enzyme activity is associated with increased risk of incident type 2 diabetes 3
- Chronic kidney disease, as elevated GGT is associated with increased risk of chronic kidney disease 3
- Cancer, as elevated GGT is linked to increased risk of various life-threatening cancers 3, 4, 5
- Metabolic syndrome (MetS) and its related disorders, as GGT is an early predictive marker for atherosclerosis, heart failure, and arterial stiffness 4
Characteristics of GGT in Different Liver Diseases
The characteristics of GGT in different liver diseases are:
- Primary biliary cholangitis (PBC) and drug-induced liver injury (DILI): highest level of GGT up to 1000.00 to 2000.00 U/L, positively correlated with ALP and TC 2
- Alcoholic liver disease (ALD): highest level of GGT more than 2000.00 U/L, positively correlated with ALT, AST, ALP, TG, and TC 2
- Non-alcoholic fatty liver disease (NAFLD): highest level of GGT only about 200.00 U/L, positively correlated with ALT, AST, and TG 2
GGT as a Predictive Biomarker
GGT is a predictive biomarker of cellular antioxidant inadequacy and disease risk, as elevated GGT is linked to increased risk of various diseases, including cardiovascular disease, diabetes, and cancer 4