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Gamma-Glutamyl Transpeptidase (GGT) Test: Why and How is it Done?

Medically reviewed by John Paul Abrina, MD · Oncology · Davao Doctors Hospital

Written by Hello Doctor Medical Panel · Updated Jul 08, 2022

    Gamma-Glutamyl Transpeptidase (GGT) Test: Why and How is it Done?

    Gamma-Glutamyl Transpeptidase (GGT) is also known as Gamma-Glutamyl Transferase. It is an enzyme found in the liver, gallbladder, pancreas, and kidneys. It is also found in your blood and other bodily fluids. The Gamma-Glutamyl Transpeptidase (GGT) test measures the amount of Gamma-Glutamyl Transpeptidase enzyme present in your blood. GGT works as a transport molecule that helps to move molecules around the body. It plays a major role in aiding the liver in digesting drugs and other toxins. High levels of GGT in the blood indicate liver damage.

    Why is a GGT test done?

    Your liver plays a significant role in the production of proteins in your body and flushing out poisons from your body. It also does the important task of helping your body process fats. Your doctor may prescribe you a Gamma-Glutamyl Transpeptidase (GGT) test if you have symptoms of liver disease. The test is currently the most efficient way to diagnose if you have liver disease or damage. The reason behind liver damage is often alcohol or drugs.

    Check for the following symptoms if you fear liver disease.

    • Nausea
    • Abdominal pain
    • Jaundice
    • Itchy skin
    • Lack of appetite
    • Stomach pain

    The test is prescribed to detect if you have any liver or bile ducts diseases. The GGT test is often prescribed with other tests to understand the difference between liver and bone diseases.

    ggt test

    GGT Test: Prerequisites

    Your doctor may ask you to avoid consumption of food for at least eight hours before the GGT test. If you are consuming any medications, herbs, or supplements, inform your doctor. Your doctor may ask you to stop or change the dosage of medications. Avoid consumption of alcohol for at least 24 to 48 hours before the test. Even a small amount of alcohol in the body can have an impact on the results.

    Phenytoin and Phenobarbital can increase the level of GGT in your blood. Birth control pills and clofibrate can decrease the level of GGT in your blood.

    Understanding the results

    The normal level of GGT varies depending on the age, gender, and medical conditions. The result of GGT test is measured in International Units per Liter or IU/L. The normal range of GGT in adults is 5 to 30 IU/L. Newborn babies will have higher levels of GGT right after birth.

    If your results display GGT level above 30 IU/L, it is an indication of liver disease. The higher the level, the more is the damage to your liver. Conditions that could increase the GGT levels are viral hepatitis, liver cancer, and bile duct blockage.

    It is important to note that high levels of GGT is not specific to liver disease. In some cases, it can be an indication of congestive heart failure or diabetes.

    High levels of GGT can be because of the following medical conditions:

    • Excess consumption of alcohol
    • Cirrhosis
    • Diabetes
    • Pancreatitis
    • Excess consumption of drugs or any medications
    • Heart failure
    • Chronic viral hepatitis

    The GGT test helps to diagnose liver disease but can not determine the cause of the disease. If the GGT results are abnormal, your doctor may prescribe you to undergo a few more tests to determine the cause.

    Liver damage is a serious condition and at times can be fatal. Pay attention to the early signs and symptoms of liver damage or disease. If the damage is diagnosed at an early stage, it will be easier to begin the treatment and reverse the damage.

    Inform your doctor if you have any symptoms of liver disease, GGT test and a few other tests will help to diagnose the disease as well as understand its cause.

    Following a healthy diet, quitting alcohol and nicotine are some of the first few steps towards maintaining a balanced GGT level. Follow up with your doctor to understand the cause of the result, discuss treatment options and precautions that need to be taken.

    When should it be repeated?

    The GGT test levels are subject to fluctuations. You might be asked to repeat the test if your doctor believes that the abnormal level of GGT in your test is the result of certain medications or alcohol. Apart from alcohol, nicotine can also have an impact on GGT levels.

    To evaluate a particular medical condition, your doctor may ask you to repeat the GGT test after a few months to confirm the recovery and monitor the effectiveness of treatment.

    If you are someone who has completed alcohol rehabilitation sessions, your doctor may prescribe you to take a GGT test at regular intervals to check if you are following the instructions provided at the sessions.

    If you are someone who consumes alcohol in huge quantities but has recently stopped, it will take over a month for the GGT levels to fall to normal range.

    GGT Test: Procedure

    GGT test is simple as a blood test and helps to measure the GGT level in the blood.

    • A nurse or health care provider will tie an elastic band around your arm. This will help to retain blood within the arm and make the veins more visible.
    • The blood is withdrawn with the help of a syringe and is collected in a vial for analysis.
    • After drawing the blood, the health professional will remove the band tied on your arm and cover the puncture area with cotton and bandage to avoid bleeding.
    • In some cases, you might also witness bruising, which might cure without any medications.
    • A mild bruise is normal and can take a few days to cure. If the bruise gets worse, seek medical help.
    • If you feel faint or lightheaded, seek medical help.
    • Inform your doctor in advance if you have any bleeding disorders.
    • Other risks associated with the withdrawing of blood are hematoma, skin infection, and excessive bleeding.

    In kids, your doctor might go with a ‘heel stick collection’. In this method, your doctor will prick your baby’s heel using a small needle and collect the blood sample.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Medically reviewed by

    John Paul Abrina, MD

    Oncology · Davao Doctors Hospital

    Written by Hello Doctor Medical Panel · Updated Jul 08, 2022

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