From the Guidelines
The Gamma-Glutamyl Transferase (GGT) test is crucial for assessing liver function and detecting potential liver damage or disease.
Key Points
- The test measures the level of GGT enzyme in the blood, with elevated levels indicating possible liver injury or conditions such as alcoholic liver disease, non-alcoholic fatty liver disease, or bile duct obstruction 1.
- A normal GGT range is typically considered to be between 0-55 U/L, although this may vary depending on the laboratory and individual patient factors.
- Elevated GGT levels can help confirm that an elevated Alkaline Phosphatase (ALP) originates from the liver and indicates cholestasis 1.
- In patients with elevated GGT levels, further evaluation and monitoring may be necessary, and in some cases, medication such as Ursodiol (ursodeoxycholic acid) may be prescribed to manage underlying liver conditions.
- The addition of GGT to a liver blood test panel increases the likelihood of an adult having abnormal liver blood tests and is associated with increased liver as well as all-cause mortality 1.
Clinical Significance
- The GGT test is essential for identifying patients with liver disease, particularly those with non-alcoholic fatty liver disease (NAFLD) or alcohol-related liver disease (ARLD) 1.
- Elevated GGT levels are associated with increased risk of liver and all-cause mortality, making it a valuable tool for risk assessment and management 1.
From the Research
Significance of Gamma-Glutamyl Transferase (GGT) Test
The Gamma-Glutamyl Transferase (GGT) test is a significant marker for various health conditions, including liver diseases and cardiovascular risk. Some key points about the significance of the GGT test are:
- GGT is a marker of oxidative stress and cholestasis, and its levels can be elevated in various 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.
- The GGT test can be used to assess the severity of liver disease and to monitor the progress of therapy, as well as to demonstrate the toxic effects of alcohol on the liver 3.
- Elevated GGT levels have been associated with an increased risk of cardiovascular events, such as congestive heart failure and components of the metabolic syndrome, including abnormal body mass index, high-density lipoprotein cholesterol, glucose, triglycerides, and systolic and diastolic blood pressure 4, 5.
- GGT has been proposed as a novel cardiovascular risk biomarker, and its levels can be used to stratify patient risk and assess the aggressiveness of appropriate treatment 4.
- In patients with Fontan-associated liver disease (FALD), elevated GGT levels have been associated with lower levels of albumin and higher levels of alanine transaminase (ALT), and a decrease in GGT levels has been associated with improvement in liver function 6.
Clinical Applications of GGT Test
The GGT test has several clinical applications, including:
- Diagnosis and monitoring of liver diseases, such as PBC, DILI, ALD, and NAFLD 2, 3, 6.
- Assessment of cardiovascular risk and stratification of patient risk 4, 5.
- Monitoring of therapy and demonstration of the toxic effects of alcohol on the liver 3.
- Evaluation of the severity of FALD and monitoring of treatment response 6.
Correlations with Other Biomarkers
GGT levels have been correlated with other biomarkers, including:
- Alanine transaminase (ALT) and aspartate transaminase (AST) in patients with ALD and NAFLD 2.
- Alkaline phosphatase (ALP) and total serum bilirubin in patients with PBC and DILI 2.
- Triglyceride (TG) and total cholesterol (TC) in patients with ALD and NAFLD 2, 5.
- Insulin resistance and metabolic syndrome components, such as abnormal body mass index, high-density lipoprotein cholesterol, glucose, and systolic and diastolic blood pressure 4, 5.