Liver Function Test (LFT)

Liver is one of the essential organs in the body. It performs various functions, including detoxification, protein synthesis and the production of biochemicals vital for digestion. Thus, it makes the liver prone to many diseases. Hence, getting LFT done for general check-ups, investigating liver diseases or assessing liver functionality is vital.

There are a variety of liver function tests that assess proteins and enzymes in the blood. Any fluctuations in these LFT test values indicate liver abnormality.

The results of the liver function test are based on the analysis of a blood sample. All the tests under the liver function test are carried out with a single sample.

Jaundice, Anaemia, Cirrhosis, Gallbladder disease

The liver function test usually measures the levels of the following enzymes: Alanine transaminase (SGPT/ALT), Aspartate transaminase (SGOT/AST), Alkaline phosphatase (ALT), Gamma-glutamyl transferase (GGT), Serum albumin, Prothrombin time (PT) and bilirubin.

Your physician may request a liver function test as a routine test or if you are experiencing any of the symptoms mentioned below -

• Abdominal pain
• Weight loss
• Nausea
• Diarrhoea
• Lack of energy or fatigue
• Jaundice
• Abnormal bleeding
• Vomiting
• Fluid retention
• Dark-coloured urine
• Light-coloured stools
• Loss of appetite

Some diseases for which a doctor can prescribe liver function tests are:

• Jaundice
• Hepatitis
• Cirrhosis
• Fatty liver
• Chronic alcoholic liver disease

Following the diagnosis, the treatment for liver disease is initiated by the hepatologist or M.D. physician.

The LFT test may assist your treating physician in determining how your treatment is ongoing and regulate the medications if necessary or modify them.

The liver function test applies to males and females, both adults and children. If you are on blood thinners, you should inform your doctor about it as it may increase prothrombin time (PT). Moreover, give a complete list of all the ongoing medications.

The liver function test is also done as a part of the pre-surgery test profile to check your fitness.

The frequency of the LFT may depend on the diagnosis. It can vary from a daily basis to a few months. For instance, acute liver disease may require frequent monitoring compared to chronic liver diseases.

The test may be repeated daily in acute cases. While in chronic cases, it may be repeated weekly or monthly depending on the severity of the symptoms.

If the abnormal result of the LFT confirms the diagnosis, your physician will prescribe the appropriate medication for a specific duration.

What to Expect During the Test

Before the Test

Usually, a Liver Function test requires no special test preparation. If you are getting this test done with another test, your healthcare provider may ask you to refrain from consuming certain food items. Always consult with your doctor before the test for best results.

During the Test

The blood sample will be drawn from a vein in your arm. Here’s what you can expect from the test:

• The area where the needle is going to be inserted is wiped clean with an antiseptic.
• A tourniquet band will be placed around your arm to make the veins more prominent.
• A needle will be inserted into the vein to draw the blood. This process might take a few seconds and during this course, you might sense a quick pinch.
• The blood will be collected in a vial or a small test tube with a label mentioning your details.

After the Test

Once the blood is collected:

• A bandage is placed over the puncture site to stop the bleeding.
• Minor bruising is common however, feeling dizzy is less common. You may be asked to sit for a few minutes.
• Get your healthcare provider if you experience bleeding, pain or rashes at the puncture site.

The liver function test includes the following parameters:

Transaminases

Aspartate (AST or SGOT) and alanine (ALT or SGPT) are enzymes present in large quantities in the liver. ALT is an enzyme primarily present in the liver. In comparison, AST is an enzyme released from the heart, liver, skeletal muscle and kidney.

Serum levels of ALT and SGOT are increased on damage to the tissues producing them. Thus, serum estimation of SGPT is specific for liver diseases. In contrast, SGOT levels may rise in case of muscle or liver cell injury.

Gamma-Glutamyl Transpeptidase (GGT)

The primary source of this enzyme is the liver. Elevation of GGT occurs in cholestasis (a condition where bile flow from the liver is blocked or stopped) and liver diseases. GGT levels are often high in patients with alcohol abuse.

Serum Albumin

Albumin is a protein that is synthesised in the liver. It performs various functions such as providing nourishment to tissues, transporting of vitamins, hormones, medications and other substances. The blood level of albumin is decreased in extensive liver damage or disease.

Serum Bilirubin

Bilirubin is a waste product made by the liver after the breakdown of red blood cells. Bilirubin is excreted in the stool via the liver. Elevated bilirubin level indicates liver disease or damage or certain types of anaemia.

Alkaline Phosphatase (ALP)

Serum alkaline phosphatase is found in the liver, bone, intestine and placenta. High ALP levels can mean cholestasis (partial or complete bile duct obstruction), bone regeneration, pregnancy and neoplastic, infiltrative and granulomatous liver diseases.

There are a wide variety of markers used to assess liver functionality, damage or disease. However, the markers mentioned above are extensively used. These LFT values provide an idea about the functioning and determine the extent of liver disease or damage. The liver function test result is not expressed as positive or negative. If the value is on the higher side or lower side, it indicates a liver disorder.

Certain enzyme levels are marginally higher in children, especially infants. Moreover, there may be a minimal difference in the normal LFT values between males and females.  

The normal values and reference ranges of the test may vary from lab to lab. Please refer to the ranges mentioned in the report and consult a doctor to understand the interpretation of lab reports.

If one or more biomarkers of the liver function test are abnormal, it might indicate liver damage or disease. Liver damage can be caused by various conditions such as hepatitis, alcoholic liver disease, liver cancer, diabetes, liver cirrhosis or jaundice.

The test result may indicate liver damage or disease; however, it may not precisely pinpoint the condition. But it does help your physician to determine the next steps.

If you heavily consume alcohol, your doctor will advise you to stop drinking. Or, if you are consuming any medication causing elevation of liver biomarkers, your physician may substitute them or stop them completely.

Your doctor may decide to investigate further for hepatitis or other infections or diseases that may affect your liver. They may advise you to undergo imaging tests such as ultrasound (USG), CT scan or recommend a liver biopsy.

The price of an LFT(Liver Function Test) can differ based on the city and the laboratory. Typically, an LFT test falls within the range of INR 400 to INR 1200. For a better understanding, here is the average cost of a LFT in some major cities in India: