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The GGT test, also known as Gamma GT or gamma glutamyl transferase, is usually ordered to check for liver problems or biliary obstruction, since in these situations the concentration of GGT is high.
Gamma glutamyl transferase is an enzyme produced in the pancreas, heart and liver, mainly, and may be elevated when any of these organs is compromised, such as pancreatitis, heart attack and cirrhosis, for example. Thus, to aid in the diagnosis of liver and biliary problems, the doctor usually requests its dosage along with TGO, TGP, bilirubins and alkaline phosphatase, which is an enzyme also dosed to assist in the diagnosis of liver problems and biliary obstruction.See what the alkaline phosphatase test is for.
This exam can be requested as a routine exam by the general practitioner or when pancreatitis is suspected, for example. However, performing this test is more recommended in cases of suspected cirrhosis, hepatic steatosis, which is fat in the liver, and excessive alcohol use. The reference value varies by laboratory and is typically between 7 and 50 IU/L.
What the changed value means
The values of this blood test should always be evaluated by a hepatologist or general practitioner, however, some changes are:
High gamma glutamyl transferase
This situation usually indicates the presence of a liver problem, such as:
- Chronic viral hepatitis;
- Decreased blood flow to the liver;
- Hepatic tumor;
- Excessive consumption of alcohol or drugs.
However, it is not possible to know what the specific problem is, and it is necessary to perform other tests such as computed tomography or ultrasound, for example, in addition to other laboratory tests. Find out which tests evaluate the liver.
In some rarer cases, these values may also be altered due to non-liver related diseases such as heart failure, diabetes or pancreatitis.
Low gamma glutamyl transferase
The low GGT value is similar to the normal value and indicates that there is no change in the liver or excessive consumption of alcoholic beverages, for example.
However, if the GGT value is low but the alkaline phosphatase value is high, for example, it may indicate bone problems such as vitamin D deficiency or Paget's disease, it is important to do more tests to evaluate this possibility.
How to prepare for the exam
The exam should be done after fasting for at least 8 hours, as GGT levels may decrease after meals. In addition, alcoholic beverages should be avoided 24 hours before the exam, as they may alter the result. Some medications should be discontinued, as they can increase the concentration of this enzyme.
It is also important to communicate when was the last time you ingested alcohol so that it is considered when analyzing the result, because even if it was not in the 24 hours prior to the exam, there may still be an increase in concentration by GGT.
When to take the Gamma-GT exam
This type of examination is performed when liver damage is suspected, especially when there are symptoms such as:
- Decreased appetite;
- Vomiting and nausea;
- Power outage;
- Abdominal pain;
- Yellow skin and eyes;
- Dark urine;
- Faces pale, like putty;
- Itchy skin.
In some cases, this exam may also be requested to evaluate people who are following an alcohol abandonment therapy, because, if they have ingested alcoholic beverages in the last few days, the values will be changed. Understand that other signs may indicate the onset of liver disease.