A liver function test (LFT) is a blood test that measures the levels of certain enzymes and proteins produced by the liver. It helps doctors assess the health of your liver and detect any potential problems.
What does a liver function test measure?
LFTs typically measure the levels of:
- Enzymes: These are proteins that help with chemical reactions in the body. When the liver is damaged, it releases these enzymes into the bloodstream. Some of the enzymes measured in an LFT include:
- AST (Aspartate aminotransferase): Found in the liver, heart, skeletal muscles, and kidneys.
- ALT (Alanine aminotransferase): Primarily found in the liver.
- ALP (Alkaline phosphatase): Found in the liver, bones, and intestines.
- GGT (Gamma-glutamyl transferase): Found in the liver, pancreas, and kidneys.
- Proteins: The liver also produces proteins that are essential for various bodily functions. Some of the proteins measured in an LFT include:
- Albumin: Helps maintain fluid balance in the body.
- Bilirubin: A yellow pigment produced when red blood cells break down.
- Prothrombin time (PT): Measures how long it takes for blood to clot.
Why is a liver function test done?
LFTs are commonly done to:
- Screen for liver disease: They can help detect early signs of liver damage, even before symptoms appear.
- Monitor liver disease: They can help track the progression of liver disease and the effectiveness of treatment.
- Evaluate the cause of liver damage: They can help identify the underlying cause of liver problems, such as hepatitis, cirrhosis, or fatty liver disease.
- Monitor the effects of medications: Some medications can damage the liver. LFTs can help monitor the liver's response to these medications.
What do the results of a liver function test mean?
The results of an LFT are interpreted in conjunction with your medical history, symptoms, and other test results. Elevated levels of certain enzymes or proteins can indicate liver damage, but they don't always mean you have a serious liver problem.
If your LFT results are abnormal, your doctor may recommend further testing or treatment.
