From the Guidelines
Gamma-Glutamyl Transferase (GGT) is a liver enzyme that indicates whether an elevated Alkaline Phosphatase (ALP) level is of hepatic or nonhepatic origin, and its elevation often suggests liver stress or damage, prompting further investigation. When explaining GGT to a patient, it's essential to convey that this enzyme is found in the liver, as well as in other organs like the kidneys, intestine, prostate, and pancreas, but not in bone 1. This distinction is crucial because it helps determine the source of an elevated ALP level.
- GGT levels can be used to confirm that an elevated ALP originates from the liver, indicating cholestasis, which is a condition where bile flow is reduced or blocked.
- Elevated GGT levels can be caused by various factors, including alcohol consumption, certain medications, liver disease, or bile duct problems, as suggested by the context of abnormal liver function tests 1.
- The test to measure GGT levels is straightforward, involving a standard blood draw, and does not require special preparation.
- If GGT levels are elevated, additional tests may be recommended to determine the underlying cause, which could involve imaging of the biliary tree or other diagnostic procedures 1.
- Understanding GGT levels is vital for monitoring liver health and making informed treatment decisions, which may include lifestyle changes, medication adjustments, or further evaluation.
From the Research
Description of Gamma-Glutamyl Transferase (GGT)
- GGT is a liver enzyme located on the plasma membranes of most cells and organ tissues, particularly in hepatocytes 2.
- It plays a crucial role in the extracellular catabolism of glutathione, the major thiol antioxidant in mammalian cells, which protects cells against oxidants produced during normal metabolism 2, 3.
- GGT is used in clinical practice to indicate liver injury and as a marker of excessive alcohol consumption 2, 3.
Clinical Significance of GGT
- Elevated GGT levels have been linked to various chronic conditions and diseases, including nonalcoholic fatty liver disease, vascular and nonvascular diseases, and mortality outcomes 2, 4, 5.
- GGT is associated with an increased risk of cardiovascular disease, such as coronary heart disease, stroke, and heart failure 4, 5, 6.
- It is also a marker of antioxidant inadequacy and increased oxidative stress, which can contribute to the development of various diseases 5, 6.
Explaining GGT to a Patient
- You can explain to a patient that GGT is a liver enzyme that helps protect cells from damage caused by oxidants.
- Elevated GGT levels can indicate liver injury or excessive alcohol consumption.
- It is also a marker for various chronic conditions and diseases, and can help identify individuals at risk of developing these conditions.
- Abnormal GGT levels can be influenced by various factors, including lifestyle and environmental factors, and can be used as a prognostic marker for disease risk 5, 6.