Liver Function Test
Liver function Test (LFT) is a group of blood tests frequently performed together to assess liver function. This test evaluates the quantity of proteins and enzymes produced by the liver, such as albumin, lactate dehydrogenase, and bilirubin. This test may be needed if you have symptoms that indicate liver problems, such as dark urine, diarrhoea, or light-coloured stools and jaundice. LFT aids in the detection of liver diseases such as cirrhosis, hepatitis, and liver injury. Additionally, patients receiving therapy for liver problems are advised to do this test.
Why LFT is done?
The Liver Function Test is done:
- As a regular medical checkup
- To diagnose suspected liver disease such as viral, alcoholic, or autoimmune hepatitis, or to measure the degree of cirrhosis (scarring of the liver).
- To monitor pre-existing liver disease and assess the effectiveness of treatments for it.
What is measured by LFT?
The liver is a wedge-shaped organ situated in the upper right abdomen. The liver aids in the production of some proteins, creates bile (an alkaline fluid that aids in the breakdown of fat), processes bilirubin (a yellowish material formed when haemoglobin breaks down), and aids in the removal of ammonia from the body. It is crucial for the metabolism of proteins, carbohydrates & lipids and also to store glycogen, vitamins and minerals. It aids in the metabolism (breakdown) of several medications.
Hepatitis A, B, C, autoimmune hepatitis, alcoholic hepatitis, cirrhosis, non-alcoholic fatty liver disease (NAFLD), bile duct obstruction, liver or bile duct cancer, and many other illnesses have an impact on the health of the liver. Numerous risk factors, such as alcohol misuse, the use of certain medicines, a sedentary lifestyle and obesity, can also have an impact on liver function. For the early diagnosis of any liver abnormalities, regular liver function monitoring is important.
The LFT is a group of tests that measure the quantity of
- Aspartate Aminotransferase (AST)
- Alanine Aminotransferase (ALT)
- Alkaline Phosphatase (ALP)
- Total protein
- Bilirubin and
- Gamma Glutamyl Transferase (GGT)
in the blood. Each component has a distinct significance and aids in understanding a specific aspect of liver function.
Interpretation
- Aspartate Aminotransferase (AST)
- Normal AST: 0-35 U/L
- Very low AST: alcoholic liver disease and malnutrition
- High AST: cirrhosis, chronic liver disease, bile duct obstruction, liver trauma, non-alcoholic fatty liver disease (NAFLD), viral hepatitis (Hepatitis A, B, C) and in patients taking medicines that are harmful to the liver.
- Alanine Aminotransferase (ALT)
- Normal ALT: 0-35 U/L
- Lower ALT: healthy liver, also seen in patients with malnutrition
- Mild to moderate increase ALT: alcoholic liver disease, cirrhosis, chronic liver disease, bile duct obstruction, liver trauma or any physical injury
- High increase ALT: acute hepatitis or in patients who have taken very high doses of some medicines
- Alkaline phosphatase (ALP)
- Normal ALP: 13-100 μ/L
- Low ALP: malnutrition and certain genetic disorders
- High ALP: bile duct obstruction, hepatitis, cirrhosis, liver cancer
- Total Serum Protein
- Normal Albumin: 3.5-5.5 g/dL; Normal Globulin: 2.0-3.5 g/dL
- Low Albumin/Globulin ratio: overproduction of globulin and reduced production of albumin, which occurs with liver cirrhosis
- High Albumin/Globulin ratio: decreased production of globulins is seen in some genetic diseases or leukaemia.
- Bilirubin
- Normal: 0.3-1.0mg/dL
- High Bilirubin: Jaundice, acute hepatocellular damage, cirrhosis, viral hepatitis, alcoholic liver disease, bile duct obstruction, liver failure and in conditions involving an unusual amount of RBC destruction
- Gamma-glutamyl transferase (GGT)
- Normal GGT: 9-48 U/L
- High GGT: liver disease, acute and chronic viral hepatitis, cirrhosis, fatty liver disease, cholestasis, alcoholic liver disease, liver tumors
- Low GGT: absence of liver disease
