Liver Function Test (LFT)

The liver function test (LFT) is a comprehensive package to assess the function of your liver by examining the levels of various enzymes and proteins in your blood. These enzymes, proteins, and bilirubin collectively determine the health of the liver. Any variation from the normal range of these enzymes can indicate a problem in your liver. On the basis of  the results, your physician can start treatment or request further tests.

The liver test or LFT test indicates the level of some essential proteins like albumin and globulin, which are normally produced by the liver. Bilirubin is a by-product of liver metabolism that is excreted through the urine. The LFT test also measures the level of functional enzymes in the liver, such as alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate aminotransferase (AST).

If a person already has a history of liver disease, then a liver function test will help in assessing its current status. At Apollo 24|7, one can find a comprehensive liver function test panel that not only calculates the basic levels of protein and enzyme but also gives a comparative analysis. The comparative analysis includes the albumin and globulin ratio.

Your physician might order an LFT blood test to rule out the following possibilities:

• Damage due to infections like hepatitis B and C
• Assess the side effects of medications, like antibiotics, statins, anti-inflammatory drugs, etc
• Check for the fatty liver due to alcohol consumption
• Check for Non-alcoholic fatty liver disease, especially in Diabetics and overweight people
   

Medically reviewed by Dr Shakti, General Physician/Internal Medicine at Indraprastha Apollo Hospitals, New Delhi

Frequently asked questions

How is the blood sample taken?

To take the blood sample, a tourniquet (elastic) band is placed tightly on the upper arm. The patient is asked to make a fist. This helps in the buildup of blood filling the veins and it becomes easy to collect the blood. The skin is cleaned before inserting the needle in the vein in order to prevent bacteria from entering. The needle is then inserted into the vein in the arm and the blood sample is collected in the vacutainer.

What are the signs and symptoms of liver disease?

The signs and symptoms of liver disease may include weakness, fatigue, loss of appetite, nausea, vomiting, abdominal swelling, pain in the abdomen, yellowing of eyes or skin (jaundice), dark urine, light-colored stool, itching, and diarrhea.

What factors can cause an increased risk for liver disease?

The factors which can cause an increased risk for liver disease include taking medications that can damage the liver, heavy intake of alcohol, viral hepatitis, or possible chances for exposure to hepatitis viruses, having a family history of liver disease, obesity, especially if a person has diabetes or high blood pressure.

What are the functions of the liver?

The functions of the liver include filtering and breaking down harmful substances from the blood which are then removed from the body in urine and stools, production of bile that helps to digest foods like fat; storing glycogen which can be used for energy, converting nutrients from the food into essential blood components, regulating clotting of blood, maintaining hormone balances, producing factors that help the immune system to fight infection, and removing bacteria from the blood.

Why is family history important in the case of liver diseases?

Certain liver conditions such as hemochromatosis (deposition of iron salts in the tissues), alpha 1-antitrypsin deficiency, and Wilson disease might be inherited from the family and can cause damage to the liver. Early detection of these diseases can help to start the treatment at the earliest.

Should I inform my doctor if I am taking any medicines?

Yes, please inform your doctor if you are taking any medicines or supplements as it might interfere with the test results.

When should I consider taking a liver test?

If you have symptoms that might be related to liver diseases such as diarrhoea, change in urine colour, jaundice and abdominal pain, then an LFT test is mandatory.

What does enzyme level indicate in an LFT test?

High levels of AST and ALT indicate liver damage due to infections like Hepatitis A, B, C and E. Also, an increase in these enzymes' levels may help in determining the severity of alcohol-related disorders, Non-alcoholic fatty liver disease, liver cancer and metabolic disorders of the liver.

What should I know about the liver test?

The LFT blood test is essential to understand the severity of the illness your liver might have. However, this test is not suitable for making a final diagnosis of the condition. You must discuss the signs and symptoms with your doctor so that he/she can order other specific tests to confirm or rule out a condition. In some cases, the doctor can also suggest a biopsy and a complete health package test.

How should I prepare for the liver function test?

An LFT blood test does not require fasting or any specific preparation.

Can a liver test diagnose the exact conditions?

The results of a liver test indicate liver inflammation and functional damage only. However, it would be difficult for your physician to point out the exact cause of liver damage by looking at these test results. The doctor will need to review your medication, take a proper history, as well as understand your family history and lifestyle habits.