From the Guidelines
Elevated gamma-glutamyl transpeptidase (GGT) is most commonly correlated with liver disease, particularly cholestatic liver disease, and can help confirm that an elevated alkaline phosphatase (ALP) originates from the liver, indicating cholestasis. This correlation is based on the fact that GGT is found in the liver and can indicate whether pathologically elevated ALP is of hepatic or nonhepatic origin 1. The elevation of GGT can occur in various conditions affecting the liver, including cirrhosis, chronic hepatitis, viral hepatitis, congestive heart failure, and ischemic cholangiopathy.
Some key points to consider when evaluating elevated GGT include:
- Concomitantly elevated GGT can help confirm that an elevated ALP originates from the liver and indicates cholestasis 1
- GGT is not found in bone, making it a useful marker to distinguish between hepatic and nonhepatic causes of elevated ALP 1
- Choledocholithiasis is the most common cause of extrahepatic biliary obstruction and elevated ALP of liver origin 1
- Isolated elevated ALP of hepatic origin that persists over time suggests a chronic cholestatic process, such as partial bile duct obstruction, primary biliary cholangitis, primary sclerosing cholangitis, or drug-induced cholestasis 1
In clinical practice, the measurement of GGT can be a useful tool in evaluating patients with abnormal liver function tests, particularly when trying to determine the origin of an elevated ALP. The combination of elevated ALP and GGT should prompt further investigation, including imaging of the biliary tree, to determine the etiology of extrahepatic or intrahepatic cholestasis 1.
From the Research
Elevated Gamma Region Labs Correlation
Elevated gamma-glutamyltransferase (GGT) levels have been correlated with various diseases and conditions, including:
- Cardiovascular disease, as GGT is a predictive marker for atherosclerosis, heart failure, arterial stiffness, and plaque 2, 3, 4
- Diabetes, with elevated GGT linked to an increased risk of gestational diabetes and type 2 diabetes 2, 3
- Metabolic syndrome (MetS), with GGT serving as a superior marker for future disease risk compared to other known mortality risk factors 2
- Liver diseases, such as viral hepatitis, obstructive liver disease, and liver cirrhosis, where GGT is used as a serum marker of cholestasis 5, 6
- Increased risk of all-cause mortality, with high serum GGT levels associated with higher mortality rates 2, 3
- Oxidative and nitrosative stress, resulting from exposure to environmental and endogenous toxins 2
- NAFLD (non-alcoholic fatty liver disease) and obstructive sleep apnea, with elevated GGT often found in patients with these conditions 4