Gamma-Glutamyl Transferase (GGT) Test: Normal Range, Procedure & Result

Health conditions, such as liver disease, stomach cancer, and inflammatory bowel disease, can cause many similar symptoms. These include fatigue, lack of appetite, and stomach pain. If you experience these, your healthcare provider may suggest a few tests, including the GGT test, to know what is going on.

GGT, or gamma-glutamyl transferase or gamma-glutamyl transpeptidase, is a common enzyme in different body organs, including the liver, and tissues. It is even found in the blood and other bodily fluids. The enzyme breaks down, changes, and moves proteins and other elements in the body.

Understanding GGT Normal Range

GGT normal range in children and adults is between 0 and 30 international units per litre. GGT normal range for newborn babies is higher than this. If your GGT level is within the normal range, you may not have liver disease.

Your liver contains the highest GGT levels, while the other organs and the blood contain minimal amounts of GGT. High GGT levels in the blood indicate that the enzyme is quickly coming out of the liver cells and spreading into your blood. It further suggests damage to the bile ducts or liver. Note that GGT levels keep rising as per the extent of liver damage in a person.

High GGT levels are a vital sign of liver damage. A GGT blood test diagnoses the leading cause of the condition. Your doctor may recommend some follow-up tests to understand why your GGT levels are raised.

Uses of GGT Blood Test

Doctors use a GGT blood test to diagnose conditions like

• Bile duct obstruction
• Jaundice
• Diabetic liver disease
• Liver cirrhosis
• Pancreatitis
• Chronic viral hepatitis
• Liver damage because of excessive alcohol intake
• Liver tumour
• Heart failure
• Bone disease
• Diabetes
• Congestive heart failure

All the conditions mentioned above can be one of the major causes of high GGT levels in the blood.

You may need a GGT test if you experience the following signs of liver disease:

• Weakness
• Fatigue
• Jaundice or a condition that turns the eyes and skin yellow
• Abdominal swelling or pain
• Loss of appetite
• Vomiting
• Nausea

Prices of GGT Test

You may also need to get a GGT blood test done if you have abnormal results on an ALP test and other liver function tests. The average price range of this test is between ₹100 and ₹500 based on availability, quality, and city.

Preparing for Your GGT Test

Before going for the GGT test, you must fast for a minimum of 8 hours. Also, avoid consuming alcohol and some medicines that can affect your test results. Among medicines, you must avoid non-steroidal anti-inflammatory drugs, including naproxen, aspirin, and paracetamol. Avoiding all products that contain alcohol, such as cough medicine and mouthwash, is best. You must also avoid smoking for as long as you can before your GGT blood test.

Procedure of GGT Test

The GGT test procedure is the same as any other lab test. A medical practitioner will draw blood from your arm using a syringe and deliver it further for diagnosis. You may get your test results within 24 hours of giving your blood sample. 

Next, you can get in touch with your doctor to interpret the results. Normal test values range between 3.0 and 28.7 IU/L in women and between 3.3 and 35.0 IU/L in men. Note that the values are higher in men than in women. Also, remember that a GGT test is very sensitive, and you must not panic about your raised GGT values. Doctors generally prescribe a second test to confirm the results and avoid misguided diagnoses.

Interpreting the Results of a GGT Test

Higher-than-normal GGT levels in the blood mean that a disease or a condition is damaging your liver. (But a GGT test is not the only way to know the cause of liver damage.) Generally, the higher the GGT level, the greater the liver damage. Your elevated GGT levels may indicate liver conditions like

• Alcohol liver disease
• Hepatitis or liver inflammation, specifically alcoholic hepatitis or viral hepatitis
• Cholestasis or blocked liver bile duct
• Cirrhosis or liver scarring
• Liver ischemia or insufficient blood flow to the liver that results in liver tissue death
• Liver cancer or liver tumour
• Non-alcoholic fatty liver disease

Your high GGT levels may also indicate other conditions, like

• Pancreatic cancer or pancreatitis
• Alcohol use disorder
• Congestive heart failure
• Diabetes
• Liver damage caused by some medicines

If you have elevated GGT levels, it does not necessarily mean that you have the above-mentioned medical conditions. Other factors can also affect your GGT levels, such as

• Smoking: Smoking can notably increase GGT levels in your blood.

• Consuming alcohol: Having even a little alcohol before the 24 hours of your GGT blood test can raise those levels. Anyway, people who drink alcohol often have higher GGT levels than those who take less than two to three drinks daily or drink heavily on special occasions only.

• Some medicines: Some medicines can also raise your GGT levels. These include phenobarbital, carbamazepine, phenytoin, and acetaminophen.

Doctors will consider several aspects of your health and different situations when interpreting your GGT levels. These include:

• How high your GGT levels are 
• Your medical past
• Whether you are experiencing any symptoms
• Results of other tests taken along with GGT

Apart from the ALP test, a doctor may suggest some liver function tests along with GGT, like

• Lactic dehydrogenase or LDH
• Aspartate aminotransferase or AST
• Alanine aminotransferase or ALT

Conclusion

It can be stressful to see an abnormal GGT test result. But do not worry, as raised GGT levels alone do not imply a major disease harming your liver. Approximately 1 in 20 individuals will have an abnormal GGT test result. The doctor will factor in many things when interpreting your results and will let you know if you require further tests to identify the cause of the abnormal levels.