What is GGT?
GGT is a liver enzyme. Typically used to detect liver function and health and a marker of alcohol consumption, it is now considered an independent risk marker for many health conditions.
Why test GGT?
You may test GGT to discover your risk factors for lifestyle diseases in time to do something about them, or to monitor long-term health markers. An initial value can be tracked over time. Another reason may be that you have a personal or family history of liver disease, insulin resistance, atherosclerosis, hemochromatosis, stroke, type 2 diabetes, kidney disease, or cancer. It can also be worth testing GGT if you are a moderate to heavy drinker, smoke, eat an unhealthy diet, take or have taken drugs, or have other lifestyle risk factors.
What do the results mean?
GGT is a liver enzyme used to monitor liver health and recent alcohol consumption. High GGT is also considered an early warning sign of other health risks including type II diabetes, stroke, and atherosclerosis.
What causes low GGT?
A low GGT is a normal and desired result. Deficient levels of GGT are usually not concerning but may be a sign of an unbalanced and nutrient-poor diet leading to vitamin and mineral deficiencies (especially magnesium and B6). A deficient level is associated with hypothyroidism, so we recommend those with deficient GGT test their thyroid hormone levels. A low or normal GGT indicates a low probability of liver disease.
Symptoms of low GGT
GGT levels are influenced by factors such as age, gender, exercise, weight, pregnancy, diet, alcohol, recreational drug use, and medications. Adult males tend to have higher levels than adult females.
Elevated GGT levels indicate that something is damaging the liver. The higher the GGT, the greater the damage to your liver. A high GGT level, regardless of other risk factors, appears to increase disease risk. If GGT is elevated, dietary and lifestyle changes can help to lower GGT.
The risk for heart disease increases around the middle of what is considered normal (for a lab’s reference range). It is therefore preferable to be below the reference range midpoint (based on age and gender).
Liver conditions that can cause high GGT include hepatitis (liver inflammation), especially viral hepatitis and alcoholic hepatitis, cirrhosis (liver scarring), cholestasis (blocked bile duct), alcoholic liver disease, non-alcoholic fatty liver disease (NAFLD), liver ischemia (lack of blood flow to the liver causing the death of liver tissue) and liver tumours/cancer. Other conditions that may affect liver function and health include pancreatitis, pancreatic cancer, diabetes, metabolic syndrome (combination of insulin resistance, high blood pressure, abnormal fat profile, and obesity), congestive heart failure, certain medications, and alcohol.
Both hypothyroidism (usually lower T3/T4 and higher TSH) and hyperthyroidism (higher T3/T4 and usually lower TSH) have been implicated in higher GGT levels.
A high GGT level can help rule out bone disease as the cause of an increased ALP level. High ALP levels are more likely to be attributable to bone disease when GGT is low or normal.
Symptoms of high GGT
High levels of gamma-glutamyl transferase (GGT) can indicate liver disease and are often associated with symptoms such as fatigue, weakness, jaundice (yellowing of the skin and eyes), dark urine, light-colored stools, abdominal pain, and nausea. Elevated GGT levels can also be linked to alcohol abuse, bile duct problems, or the use of certain medications.
More information
Recent studies suggest that GGT measurements may predict the odds of health risks such as atherosclerosis, stroke, metabolic syndrome, type 2 diabetes, kidney disease, cancer, and all-cause mortality in both men and women. These studies suggest that there is an increased risk of the disease once GGT rises above the “low-normal” range for gender, even if GGT is within the ‘normal’ range.
For some people, it might be important to test GGT regularly. A 7-year Austrian study of 76,000 people found that irrespective of the original GGT measurement, individuals whose GGT concentrations increased over time had more disease and mortality risk. A decreasing GGT value resulted in a lower risk. Lower initial GGT always indicated less risk than higher. This was particularly important in men under 60 and women under 65.
Preparations for this test
The day before the test
Avoid fatty foods and alcohol today.
On the day of the test
Always take I.D. with you when going to take a test.