Liver Function Test

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WHAT IS A LIVER FUNCTION TEST? A liver function test can be described as a blood test that serves to diagnose and check damages or diseases to the liver by measuring the level of certain enzymes and proteins in the body.  A liver function test can also measure the rate at which the liver carries… Read More

Liver Function Test


A liver function test can be described as a blood test that serves to diagnose and check damages or diseases to the liver by measuring the level of certain enzymes and proteins in the body. 

A liver function test can also measure the rate at which the liver carries out its normal function by the production of enzymes that the liver cells produced when damaged or diseased and clearing bilirubin which is a blood waste product and also possible. 

However, if your liver function test is abnormal, you don’t need to be scared, it doesn’t necessarily mean that your liver is damaged.


A liver function test is normally done for the following reasons:

  • To ascertain liver infection such as hepatitis–type B and C, cirrhosis, etc.
  • To check for the progression of a viral disease 
  • To measure the effect of alcohol on the liver 
  • To check how the liver is responding to treatment.
  • To evaluate the severity of the scarring of the liver.
  • To check for possible complications of treatment. 
  • A liver function test is also used to check your enzyme and protein level in the blood.


The different types of liver function tests are derived from testing for the level of the different enzymes present in the liver. They include:

  • Alanine Transaminase or Aminotransferase (ALT)

Alanine transaminase is an enzyme located in the liver which helps in the conversion of protein into energy which is needed by the liver cells. When there is damage or there is the presence of a disease, alanine transaminase is released and its level in the blood increases.

  • Alkaline Phosphate (ALP) 

Alkaline phosphate can be used to describe an enzyme that aids in metabolizing proteins in the body and is found in the liver and bone. When ALP levels high in the blood, it indicates that there may be damage to the liver or an infection to the liver, a blockage to the bile duct, or an infection on the bone. However, high levels of ALP may be due to pregnancy, and growing bones in children. The normal level for ALP is 120 international units per liter.

  • Aspartate Transaminases or Aminotransferase (AST)

Aspartate transaminases liver test is a type of liver function test that shows the level of the enzyme “aspartate transaminases”. This is also called “Serum Glutamic-Oxaloacetic Transaminase (SGOT)”.

Aspartate transaminases is an enzyme found in some parts of the body mostly the liver, the heart, and muscles, and is often released into the bloodstream when there is a liver injury and in large quantities.

The AST liver function test normal values is about 40 international units per liter for adult and slightly higher in children. An increase shows the presence of damage to the liver or muscle. 

  • Total Protein 

This is the measurement of the total amount of proteins in the body. There are two main forms of protein:

  • Albumin

This protein is produced in the liver and aids in the transportation of hormones, enzymes, minerals, bilirubin, and medications all through the body also assists in stopping the leakage of fluids out of blood vessels.

  • Globulin

This is a protein that is produced by the immune system’s cells in the liver.  It fights against diseases and infections in the body and also assists in the transportation of enzymes, hormones, minerals, etc throughout the body. 

The test can separately measure albumin, globulin, total protein, and also, albumin/globulin ratio (A/G ratio)

  • Bilirubin

Bilirubin is the waste product gotten from the breakdown of the red blood cells and eliminated by the liver. When the bilirubin level in the body increase, then it could indicate a liver breakdown.

Bilirubin liver function test measures these forms of bilirubin:

  • Unconjugated (Indirect) Bilirubin

The hemoglobin releases heme which is converted to bilirubin and this is called unconjugated bilirubin. This bilirubin is carried by some proteins to the liver.

  • Conjugated (Direct) Bilirubin

In the liver, the indirect bilirubin gets attached to glucuronic acid, which is a modified sugar, and forms conjugated bilirubin.

  • Total Bilirubin

This is the total number of both indirect and direct bilirubin in the body.

  • Gamma Glutamyl transferase (GGT)

These are enzymes that an increase in their level in the blood could indicate liver damage.


People who are eligible for a liver function test include: 

  • Those who are suspected of having hepatitis either type B or C.
  • People are suspected of having a liver malfunction.
  • People with gall bladder disease.
  • Alcohol addicts. 
  • And if your doctor recommends it to properly diagnose you.


A liver function test is s safe test with few side effects which are soreness and bruising at the place the blood samples were taken, too much bleeding, feeling of dizziness, etc.


When preparing for a liver function test you need to be careful of certain food and medications you take as it could affect the result of the test. Sometimes, your doctor may recommend that you avoid food and medications during the period of the test and try drinking enough water. Let your doctor know the medications you are taking


Before the Test,

You might need to avoid eating or drinking at least for some hours before your test. Then you will be taken to the lab to get your blood sample.

During the Test,

A lab technician will take your blood sample by inserting a needle into your veins and withdrawing blood samples into a tube attached to the needle, tour might experience slight pain after which you will feel nothing.

After the Test,

Your blood sample will be taken and carried to the lab for analysis. You are free to go home and the result may take some minutes or hours to be out. You can eat and drink after the test is done and try resting if you feel dizzy or lightheaded 


(What Are The Results Of Liver Function Test Interpretations?)

The result is dependent on the type of liver test conducted, and the level of the enzyme found in the blood. The result may be affected by sex and age. However, your doctor will help you interpret the result accurately and help you diagnose your clinical conditions and if you are having a liver infection, the liver function test will reveal it.  

Liver Function Test Normal Range Chart

Liver Function Test Normal Values of Liver Function Test Liver Function Test Interpretations
ALT The normal range of ALT is between 0 – 30 U/L. Lower levels of ALT can be seen as normal indicating a normal liver. Although sometimes, very low levels can indicate malnutrition.


Moderate levels can indicate liver problems and trauma such as liver injury, cirrhosis, bile duct obstruction, alcoholic or chronic liver disease, etc.


Higher levels of ALT indicate hepatitis or intake of high doses of medications such as paracetamol or ibuprofen.

ALP The normal level of ALP is 13 – 300 U/L. Low levels of ALP may indicate the presence of some genetic disorders or malnutrition. It can also be an aftermath of a blood transfusion or heart transplant.


A high range of ALP may signify liver damage or disease such as cancer, cirrhosis, hepatitis, bile don’t instruction, etc. However, in pregnant women or a growing child, high levels can be treated as normal.

AST AST normal range is  between 0 to 35 IU/L (international units per liter) ALT low levels are regarded as normal but very low levels can signify malnutrition or alcoholic liver problems.


High levels of ALT indicate that high doses of liver harming medications such as paracetamol are taken. Also, it may be a signal of liver damage or diseases such as cirrhosis, hepatitis, non-alcoholic fatty liver disease (NAFLD), etc.

Total Protein Total protein normal value ranges between 5.5 – 9g/dL (grams per deciliter).

Albumin normal range is 3.5 – 5.5g/dL of blood.

Globulin’s normal value is between 2.0 – 3.5g/dL.

A/G ratio normal value is slightly >1g/dL.

Low levels of albumin indicate that something is wrong with the liver. The synthesizing, digesting, and absorption function of the liver is defective. It can also indicate the presence of liver disease such as cirrhosis, hepatocellular necrosis,  inflammatory liver diseases, etc.

Higher levels of albumin indicate intake of protein-rich diet or liver infections such as hepatitis.


Globulin low levels may indicate malnutrition, while high levels indicate liver infection and inflammatory disease such as hepatitis.


A high A/G ratio signifies the reduced production of globulin which is often an indicator of some genetic disorders such as leukemia. A Low A/G ratio indicates a decreased production of globulin and reduced production of albumin which suggests cirrhosis.

Bilirubin The normal value for unconjugated bilirubin is between 0.2 – 0.7mg/dL.

For conjugated bilirubin, the normal range is between 0.1 – 0.3mg/dL.

Total bilirubin normal value is between 0.3 – 1.0mg/dL.

For unconjugated and conjugated bilirubin, lower levels are considered normal.


However, higher levels of unconjugated bilirubin may suggest different conditions and liver problems like jaundice, hemolysis, acute hepatocellular damage, hepatitis, cirrhosis, etc.


High levels of conjugated bilirubin are indicative of hepatitis, bile duct inflammation, gallstones.

GGT The normal levels of GGT in the blood are between 0 – 51 IU/L. When GGT levels in the blood are low, it shows the absence of liver disease and alcohol and is seen as normal.


Elevated levels of GGT are indicative of a high intake of medications such as paracetamol, antidepressants, phenobarbitone, etc. It can also indicate the presence of liver problems such as a tumor, hepatitis, cholestasis, chronic, alcoholic, or fatty liver disease, etc.



The cost of the liver function test varies according to the lab conducting the analysis and the country/city where the test was conducted. 

However, there are some discounts in certain places and Anavara, with several connections with different hospitals and labs, can help connect you to very affordable labs and hospitals for your liver function test. 


  • What is the most common liver function test?

Liver function tests are tests employed in other to ascertain the level of certain enzymes and protein in our blood. Some common liver function test includes alanine transaminase test, aspartate aminotransferase test, alkaline phosphate test, and bilirubin test

  • Does alcohol affect the liver?

The liver can be affected by too much intake of alcohol and its metabolic process may be slowed or affected. You may need to reduce or stop your alcohol intake depending on the level of damage to your liver,

  • What kind of medications affects the liver?

Certain medications could affect the liver by increasing the liver enzyme in the blood and they include acetaminophen, diclofenac, naproxen, cholesterol-lowering medications, some antibiotics, some antifungal medications, etc

  • What are the less common causes of abnormal liver enzymes?

There other causes of abnormal increase in liver enzymes and they include Wilson disease which is due to excess accumulation of copper in the body, cancerous growth in the liver, pregnancy, gall stones, ulcerative colitis, obesity, etc

  • Does a liver function test show liver damage?

A liver function test helps check if your liver is working properly by assessing some abnormal signs in the body and can help give relevant information to the condition of your liver and possibly diagnose any damage to it.