Purpose of Liver Function Test (LFT)
Liver function tests (LFTs) are a group of blood tests that are used to evaluate the overall function of the liver. These tests are usually ordered by a doctor when a patient is experiencing symptoms that may indicate a problem with their liver, or as part of routine health screening. The purpose of LFTs is to help identify any liver damage or disease, and to monitor the progression of liver disease and the effectiveness of treatments.
LFTs typically include the following tests:
Alanine transaminase (ALT) and aspartate transaminase (AST): These enzymes are released by damaged liver cells and are used to evaluate liver function and to detect liver damage or disease.
Alkaline phosphatase (ALP): This enzyme is found in bile ducts and bone, and increased levels of ALP may indicate liver damage or disease.
Gamma-glutamyl transferase (GGT): This enzyme is found in liver cells and bile ducts, and increased levels of GGT may indicate liver damage or disease.
Bilirubin: This is a waste product of red blood cell breakdown that is processed by the liver. High levels of bilirubin may indicate liver disease or other conditions that affect the liver.
LFTs are also used to monitor the effectiveness of treatments for liver disease, such as medication or lifestyle changes, and to assess the risk of complications associated with liver disease, such as cirrhosis or liver failure.
It’s important to note that abnormal results on LFTs do not necessarily mean that a person has liver disease or damage, and further testing may be needed to make a diagnosis.
Normal Range of Liver Function Test Parameters
The normal range for liver function test (LFT) parameters can vary slightly depending on the laboratory and testing methods used, but generally the following are considered normal ranges:
- Alanine transaminase (ALT): 7 to 55 units per liter (U/L) for men, and 7 to 45 U/L for women
- Aspartate transaminase (AST): 8 to 48 U/L for men, and 8 to 33 U/L for women
- Alkaline phosphatase (ALP): 45 to 115 U/L for adults
- Gamma-glutamyl transferase (GGT): 9 to 48 U/L for men, and 9 to 32 U/L for women
- Total bilirubin: 0.1 to 1.2 milligrams per deciliter (mg/dL)
It’s important to note that these are general ranges and may vary depending on the laboratory and testing methods used, as well as a person’s age, sex, and other health factors. Abnormal results on LFTs may indicate liver disease, damage, or other medical conditions, and further testing may be needed to determine the cause. It’s important to discuss any abnormal results with a healthcare provider.