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◉ What is GGT blood test?
The GGT blood test, or gamma GT, is a laboratory test that measures the levels of the Gamma-glutamyl transferase enzyme in the blood. GGT is predominantly found in the liver, but it is also present in other organs such as the kidney, pancreas, and intestines.
The GGT blood test is often used to assess liver function and to help diagnose or monitor conditions that affect the liver, such as liver disease, bile duct obstruction, alcohol abuse, or certain medications that can cause liver damage.
Despite its high sensitivity in the context of liver diseases, gamma GT has low specificity, which means that it must be interpreted taking into consideration other examinations and clinical elements.
◉ Other names
- Gamma GT.
- GGT.
- γ-GT
- Gamma-glutamyl transferase.
- Gamma-glutamyl transpeptidase.
◉ Why it is done?
The GGT blood test is often used as a marker of liver function and to help diagnose or monitor conditions that affect the liver. It is commonly performed to
- Assess liver health: High GGT levels may indicate liver dysfunction or damage, such as hepatitis, cirrhosis or fatty liver.
- Detect bile duct obstruction: An increase in gamma GT levels may be an indicator of bile duct obstruction or blockage, which can be caused by conditions such as gallstones or tumors.
- Monitor alcohol consumption: This enzyme can be used as a marker to assess alcohol abuse or alcohol-related liver disease.
- Assess medication side effects: Some medications, such as antiepileptics, cholesterol-lowering medications, or certain antibiotics, can cause liver damage as a side effect.
◉ Preparation and blood sampling
No specific preparation is generally necessary before a GGT blood test. However, it is always advisable to follow the instructions provided by your healthcare professional or the laboratory where the test will be performed. These instructions may include:
- Fasting: In most cases, fasting is not necessary for gamma GT dosing. However, if you are scheduled to have other liver function tests at the same time, your doctor may recommend that you fast for a period of time before the test.
- Medications: Tell your doctor about any medications, supplements, or herbal products you are currently taking.
- Inform your doctor: Be sure to tell your doctor about any health problems you have, including any liver or kidney disease.
◉ Normal GGT levels
Normal levels of GGT in blood may vary slightly depending on the laboratory and reference values used. However, in general:
- In adult males: 8 to 60 units per liter (U/L)
- In adult females: 5 to 40 U/L
Note
- Results may be influenced by pregnancy, childbirth, race, smoking, oral contraceptive use and exercise.
- Pregnancy is associated with decreased GGT activity, while postmenopausal women and those taking oral contraceptives have higher levels.
◉ High GGT levels
Elevated levels of GGT test have been reported in a wide range of clinical conditions, including liver and pancreatic diseases, myocardial infarction, renal failure, diabetes and alcoholism
In the case of liver diseases, gamma GT levels can be elevated in conditions such as:
- Hepatitis (acute and chronic)
- Cirrhosis
- Liver metastases and carcinoma
- Cholestasis (reduction or cessation of bile flow).
- Chronic alcoholic liver disease
Other causes of elevated GGT may include:
- Pancreatitis.
- Carcinoma of the prostate, breast and lung.
- Certain autoimmune diseases.
- In addition, some medications, such as certain anti-epileptic drugs, cholesterol-lowering drugs, or certain antibiotics, can cause liver damage as a side effect.
◉ Low levels of GGT
Low levels of GGT in the blood below 8 U/L in males and below 5 U/L in females may not necessarily indicate a specific medical condition or health concern. In some cases, low GGT levels can be considered normal and within the reference range.
However, if the GGT levels are consistently low and other liver function tests indicate abnormalities, it may be worth further investigation to determine the underlying cause some potential reasons for low GGT levels include:
- Normal variation: GGT levels can vary among individuals, and some people naturally have lower levels of GGT.
- Liver disease: In rare cases, certain liver diseases or conditions can cause decreased Gamma GT levels. This may be seen in conditions with severe liver damage, advanced cirrhosis, or late stages of alcoholic liver disease.
- Genetic factors: Some studies suggest that certain genetic factors or variations in the GGT gene itself can result in lower GGT levels.
- Drug use: Certain medications or substance abuse, particularly alcohol consumption, can affect liver enzymes, including GGT levels. If a person ceases or significantly reduces drug or alcohol use, GGT levels may decrease.
◉ How to reduce a Gamma GT level that is too high?
- Reduce or completely stop alcohol consumption if the elevation in gamma gt is due to alcoholism.
- Treatment of diseases such as hepatitis, gallstone disease, or other underlying conditions involved.
- Healthy diet and physical activity.
- Treatment of glycemic or lipid imbalance
- Review the intake of certain medications or adjust doses with your doctor.
◉ Additional tests
In addition to the GGT blood test, there are several other tests that can be done to evaluate liver function and assess liver health. These may include:
- Alanine aminotransferase (ALT): ALT is an enzyme found primarily in liver cells. Elevated levels of ALT in the blood can indicate liver damage or inflammation.
- Aspartate aminotransferase (AST): AST is an enzyme found in various organs, including the liver. Elevated levels of AST can indicate liver disease or damage.
- Alkaline phosphatase (ALP): ALP is an enzyme found in various tissues, including the liver, bones, and intestines. Elevated levels of ALP can indicate liver or bone disorders.
- Bilirubin: Bilirubin is a waste product produced during the breakdown of red blood cells. Elevated levels of bilirubin can indicate liver disease or other conditions affecting the liver's ability to process bilirubin.
- Prothrombin time (PT) and International Normalized Ratio (INR): These tests assess the blood's ability to clot and can help evaluate liver function, as the liver produces many clotting factors.
- Albumin: Albumin is a protein produced by the liver. Low levels of albumin can indicate liver disease or dysfunction.
- Hepatitis B and C screening: These blood tests check for the presence of hepatitis B or C viruses, which can cause liver inflammation and damage.