From the Guidelines
Concerning levels of Gamma-Glutamyltransferase (GGT) are typically above 224 IU/L.
Rationale
- The study by 1 found that a GGT level of 224 IU/L had a sensitivity of 80.6% and a specificity of 75.3% for detecting common bile duct stones.
- Elevated GGT levels can indicate liver disease, particularly cholestatic liver disease, as it is found in the liver and can be elevated in conditions such as primary biliary cholangitis, primary sclerosing cholangitis, and intrahepatic or extrahepatic bile duct obstruction 1.
- GGT is often used as a marker for alcohol-related liver disease, but its specificity for alcohol decreases in advanced liver disease due to elevation in patients with extensive fibrosis regardless of the cause 1.
- The following key points support the concerning level of GGT:
- GGT is usually higher in patients with alcohol-related liver disease compared to those with other liver diseases 1.
- Serum GGT activity loses its specificity for alcohol in more advanced liver disease 1.
- Elevated GGT levels can be seen in various liver conditions, including cholestatic liver disease, and are not specific to alcohol-related liver disease 1.
Key Considerations
- GGT levels should be interpreted in the context of other laboratory tests and clinical findings, as isolated elevation of GGT may not be specific for liver injury 1.
- The cutoff value of 224 IU/L is based on a specific study and may not be universally applicable; however, it provides a general guideline for concerning GGT levels.
From the Research
Concerning Levels of Gamma-Glutamyltransferase (GGT)
The concerning level of Gamma-Glutamyltransferase (GGT) is not explicitly stated in the provided studies. However, the studies suggest that elevated GGT levels are associated with increased risk of various diseases and conditions, including:
- Cardiovascular disease 2, 3, 4, 5
- Diabetes 2, 3, 4
- Metabolic syndrome 2, 3, 4, 5
- Liver disease 2, 6
- Cancer 2, 3
- Chronic kidney disease 3
- Mortality 2, 3, 4
Association with Disease Risk
The studies consistently show that elevated GGT levels are associated with increased risk of disease, even within the normal reference range 3, 4. The risk of disease increases with increasing GGT levels, with a 20% per GGT quartile trend rise in the risk of metabolic syndrome 4 and a 26% per quartile increased risk of all-cause mortality 4.
Clinical Significance
GGT is considered a valuable adjunct in stratifying patient risk and assessing the aggressiveness of appropriate treatment 4. The enzyme is also linked to oxidative stress and may be a proatherogenic marker 4. Further assessment of the use of GGT as a prognostic marker, together with the presence of the metabolic syndrome, is suggested 5.