Gamma-Glutamyltransferase (GGT)
Gamma-Glutamyltransferase (GGT): What It Is and Why the Test Is Prescribed
Gamma-Glutamyltransferase (GGT) is an enzyme involved in amino acid metabolism and glutathione transport. It is mainly active in liver cells, bile ducts, pancreas, kidneys, and other organs. GGT is present in small amounts in the blood, and its elevation usually indicates hepatobiliary system pathologies.
Reasons for GGT testing
- Diagnosis and differential diagnosis of liver and bile duct diseases
- Assessment of liver damage severity in various conditions (hepatitis, cirrhosis, fatty liver, tumors)
- Monitoring alcoholism treatment and hepatotoxicity of medications
- Detection of mechanical jaundice, cholangitis, cholecystitis, bile duct obstructions
- Screening and monitoring of patients with chronic alcoholism
When GGT levels increase
Significant GGT elevation is observed in:
- Obstructive jaundice, cholangitis, cholecystitis — 5–30 times above normal; GGT rises earlier and remains elevated longer than other liver enzymes
- Liver metastases — 12 or more times above normal
- Acute and chronic hepatitis — 2–5 times above normal
- Cirrhosis, fatty liver, pancreatitis, pancreatic tumors
- Alcohol abuse — GGT serves as a marker of alcoholic liver damage; levels decrease gradually after cessation
- Use of certain drugs (antidepressants, antibiotics, hormonal contraceptives, phenobarbital, furosemide, etc.)
Other causes of GGT elevation
- Diabetes mellitus
- Obesity
- Hyperthyroidism
- Radiation liver damage
- Kidney diseases (glomerulonephritis, pyelonephritis)
- Prostate, breast, lung tumors (especially with liver metastases)
- Infectious mononucleosis
Diagnostic value
GGT is a sensitive but nonspecific marker of liver and bile duct damage. For accurate diagnosis, GGT results are interpreted together with other biochemical markers (ALT, AST, alkaline phosphatase).
Normal GGT values
- Men: 11–50 U/L
- Women: 7–32 U/L
- Newborns and children have higher values than adults
Preparation for the test
- Blood should be drawn fasting (8–12 hours fasting)
- Avoid physical and emotional stress, alcohol, and medications (consult doctor) 24 hours before the test
- Do not smoke for at least one hour before the test
Conclusion:
GGT is an important laboratory marker for detecting and monitoring liver and bile duct diseases, as well as for monitoring alcoholism treatment and hepatotoxicity of drugs. Elevated GGT requires comprehensive patient evaluation and additional diagnostics.