Liver Function Tests
What are Liver Function Tests?
Liver function tests, which are also called hepatic function panel, is a cluster of blood tests that examine different aspects of the liver’s functioning. These are mainly AST, ALT, ALP, GGT, PT, albumin and bilirubin levels.
Why is it conducted?
- The liver has multiple functions and the levels of various enzymes and proteins in the blood are the clearest indication of the liver’s condition.
- It can indicate infections or any kind of damage to the liver through medicines, alcohol or other factors.
- It can also help to study the progress of existing liver diseases and the efficacy of the treatment being followed.
Who should go for it?
As the liver plays a role in a number of bodily processes such as digestion, metabolizing drugs and clearing toxins, making proteins, storing energy, blood clotting and so on. Therefore a number of health conditions can be traced through liver function tests.
- People who are taking medications that are known to cause damage to the liver such as paracetamol.
- People who drink alcohol excessively.
- Persons who have symptoms that indicate liver damage such as nausea, pain in the abdomen area and so on.
- Persons who have yellowing of the skin which is the clearest symptom of jaundice.
- People who exhibit signs of easy bruising, that is, getting large bruises even with a mild collision.
- Persons who have dark urine along with stools that are light colored as it may indicate biliary problems.
- People with unexplained whole body itching should opt for liver function tests as this indicates liver disease.
- Persons who may have been exposed to Hepatitis infection.
- People with water retention in the abdomen area.
This is a simple blood test and the technician will draw the blood from a vein in the arm or the back of the hand.
Interpretation of results
The results of the liver function tests cannot be interpreted in isolation. Often the ratio of the various enzymes in relation to each other is also taken into consideration as a distinct pattern can be seen in different types of liver problems. Enzymes like ALT and AST can also be high due to factors other than liver injury, such as muscle injury. Furthermore certain medications like statins, antibiotics, barbiturates may influence test results. Besides, conditions like pregnancy, age and gender of the person is also important as the normal ranges for children are different. In short, these tests indicate:
- aspartate aminotransferase (AST or SGOT)-this is present in other parts of the body too and it alone does not indicate liver disease.
- alanine aminotransferase (ALT or SGPT)- this is mainly present in the liver and its high levels in the blood indicate liver disease.
- alkaline phosphatase, (ALP)- high levels of this enzyme indicates liver damage or bone disease.
- gamma-glutamyl transpeptidase (GGT)- this along with ALP can indicate diseased liver or bile ducts.
- albumin level – albumin is made in the liver and low levels indicate severe liver disease.
- bilirubin level –indicates levels of conjugated and unconjugated bilirubin in the blood which may be due to liver or biliary problems.
- prothrombin time (PT) - this checks for blood clotting time.
Written by: Nandita tripati
Date last updated: January 07, 2015