The liver plays an important role in maintaining overall health and well-being. It performs various functions from detoxifying harmful substances to producing important proteins. To assess the health and performance of the liver, medical professionals often rely on liver function tests (LFTs). In this article, we shall discuss in detail the details of liver function tests, their importance and how they can help in the diagnosis and monitoring of liver related conditions.

Late-stage scarring of liver illustration

What are liver function tests?

Liver function tests are a series of blood tests that provide valuable insight into liver function. These tests help doctors evaluate liver health, diagnose liver diseases, monitor ongoing treatments, and assess the effectiveness of medications. LFTs measure the levels of certain enzymes, proteins, and other substances in the blood, which may indicate liver damage or dysfunction.


Common liver function tests


Alanine aminotransferase (ALT): ALT is an enzyme found primarily in liver cells. Elevated levels of ALT in the blood may indicate liver damage or inflammation.

Aspartate aminotransferase (AST): Similar to ALT, AST is an enzyme present in the liver and other organs. Elevated AST levels may indicate liver injury or other medical conditions.

Alkaline phosphatase (ALP): ALP is an enzyme found in various tissues, including the liver. Elevated ALP levels may indicate liver or bone-related conditions.

Total Bilirubin: Bilirubin is a yellow pigment that is produced when red blood cells break down. High levels of total bilirubin may indicate liver disease or other disorders that affect the liver’s ability to process bilirubin.

Albumin: Albumin is a protein synthesized by the liver. A low level of albumin in the blood may indicate liver damage or dysfunction.

Prothrombin Time (PT): PT measures the time it takes for blood to clot. Abnormal PT values can be a sign of liver diseases that affect blood clotting.

Gamma-glutamyl transferase (GGT): GGT is an enzyme found in the liver, bile ducts, and other organs. Elevated GGT levels may indicate liver or bile duct disorders.


Why are liver function tests important?

Liver function tests are necessary for several reasons:


Diagnosis of liver diseases: LFTs can help identify liver diseases such as hepatitis, cirrhosis, fatty liver disease, and liver cancer. Abnormal test results may prompt further investigation and aid in early diagnosis.

Treatment monitoring: Liver function tests are used to monitor the effectiveness of treatments for liver diseases. Regular testing helps doctors evaluate response to medications, lifestyle changes, or surgical interventions.


Assessment of overall liver health: LFTs provide an overall picture of liver health, helping doctors evaluate liver function and detect any abnormalities.


Preparing for Liver Function Tests
Before having a liver function test, some preparations may be necessary:

Fasting: Some liver function tests require fasting for a specific period of time beforehand. Your doctor will give instructions regarding fasting, if necessary.

Drug Review: Inform your healthcare provider about any drugs, supplements or herbal remedies you are currently taking, as they may affect the test results.


Interpreting Liver Function Test Results
Liver function test results are usually interpreted by comparing the obtained values with reference ranges. Abnormal results may indicate liver disease, but further testing is often needed to establish a definitive diagnosis.

It is important to note that liver function tests are just one aspect of assessing liver health. Additional tests, imaging studies, and clinical evaluation by a health care professional are often necessary for a comprehensive diagnosis.


Liver function tests are valuable tools in evaluating liver health, diagnosing liver diseases, and monitoring treatment progress. By analyzing specific enzymes, proteins, and substances in the blood, these tests provide insight into liver function and possible abnormalities. If you are concerned about the health of your liver or are experiencing symptoms related to liver disease, consult a healthcare professional who can guide you through appropriate liver function tests and their interpretation. Remember, early detection and proper management are the keys to maintaining a healthy liver and overall well-being.