Liver Function Test: A comprehensive guide

Overview of Liver Function Test

Liver function tests (LFTs) are a set of blood tests used in the diagnosis and monitoring of liver disease or damage. The tests measure the levels of certain enzymes and proteins in your blood.

The liver is one of the largest and metabolically active organs. As such its affected by many disease processes both within the liver and from elsewhere in the body

Functions of the liver:

For us to understand the disease processes that affect the liver, it’s important to briefly review what exactly the liver.

Here is a brief summary 

The liver is a critical organ for the metabolism of a wide array of substances essential for normal body functions. These include:

1. Protein Synthesis:

 The liver plays a crucial role in synthesizing proteins, including albumin, clotting factors and other essential proteins involved in immune function and the transportation of molecules in the bloodstream.

2. Bile Production:

 The liver produces bile, a substance that aids in the digestion and absorption of dietary fats. Bile is stored in the gallbladder and released into the small intestine to emulsify fats and facilitate their breakdown by enzymes.

3. Glucose Regulation: 

The liver helps regulate blood sugar levels by maintaining a balance between glucose production and storage. It stores excess glucose as glycogen and releases it when the body needs additional energy. The liver also plays a role in gluconeogenesis, synthesizing new glucose from non-carbohydrate sources.

4. Lipid Metabolism: 

The liver is involved in lipid metabolism, including the synthesis, breakdown, and transport of lipids (fats) in the body. It produces triglycerides, cholesterol, and lipoproteins and helps regulate their levels in the bloodstream.

5. Detoxification and Metabolism of Drugs:

The liver metabolizes and detoxifies various substances, including drugs, toxins, and metabolic waste products. It breaks down these substances into less harmful forms that can be excreted by the kidneys or eliminated through bile.

Understanding how the liver works is important in understanding the basis of liver function tests. Most either detect decreased levels of substances that the liver makes or increase of substances the liver excretes. That makes sense, right?

Abnormal liver function test results don’t always indicate liver disease. Your doctor will explain your results and what they mean.

Indications: Why LFTS are done

Your doctor will request Liver function tests as part of the diagnosis or management of various conditions. Some of the common indications include the following, which by no means exhaustive: 

• Screen for liver infections, such as hepatitis, liver abscess
• Monitor the progression of a disease, such as viral or alcoholic hepatitis, and determine how well a treatment is working
• Measure the severity of a disease, particularly scarring of the liver (cirrhosis)
• Monitor possible side effects of medications
• Aid diagnosis of coagulation disorders like excessive bleeding
• In pregnancy, to evaluate a dangerous condition called pre-eclampsia
• Assessment for preparation for major surgery, transplants etc
• As part of regular health checkups
• Assessment of liver lumps or malignancies

Components of Liver function tests

LFTs are panel tests meaning a number of tests carried out together. Liver function tests check the levels of certain enzymes and proteins in your blood. Levels that are higher or lower than normal can indicate liver problems. Some common liver function tests include:

Alanine transaminase (ALT). 

ALT is an enzyme found in the liver that helps convert proteins into energy for the liver cells. When the liver is damaged, ALT is released into the bloodstream and levels increase.

Aspartate transaminase (AST). 

AST is an enzyme that helps metabolize amino acids. Like ALT, AST is normally present in blood at low levels. An increase in AST levels may indicate liver damage, disease or muscle damage.

Alkaline phosphatase (ALP).

ALP is an enzyme found in the liver and bone and is important for breaking down proteins. Higher-than-normal levels of ALP may indicate liver damage or disease, such as a blocked bile duct, or certain bone diseases.

Albumin and total protein.

Albumin is one of several proteins made in the liver. Your body needs these proteins to fight infections and to perform other functions. Lower-than-normal levels of albumin and total protein may indicate liver damage or disease.

Bilirubin. 

Bilirubin is a substance produced during the normal breakdown of red blood cells. Bilirubin passes through the liver and is excreted in stool. Elevated bilirubin levels (jaundice) might indicate liver damage or disease or certain types of anaemia.

Gamma-glutamyl transferase (GGT). 

GGT is an enzyme in the blood. Higher-than-normal levels may indicate liver or bile duct damage.

Lactate dehydrogenase (LDH). 

LD is an enzyme found in the liver. Elevated levels may indicate liver damage but can be elevated in many other disorders.

Prothrombin time (PT). 

PT is the time it takes your blood to clot. Increased PT may indicate liver damage but can also be elevated if you’re taking certain blood-thinning drugs, such as warfarin.

It’s important to note there are many more analytes that can be included but are beyond the scope of this overview article.

How to prepare for the LFT test

Certain foods and medications can affect the results of your liver function tests. Your doctor will probably ask you to avoid eating food and taking some medications before your blood is drawn.

How the test is done

The blood sample for liver function tests is usually drawn through a small needle inserted into a vein in the bend of your arm. The needle is attached to a small tube, to collect your blood. You may feel a quick pain as the needle is inserted into your arm and experience some short-term discomfort at the site after the needle is removed.

After the test

Your blood will be sent to a laboratory for analysis. If the lab analysis is done on-site, you could have your test results within hours. If your doctor sends your blood to an off-site laboratory, you may receive the results within several days.

Results for Liver Function Tests

The turn around time for LFTs is usually a few hours to 24hours. Once the test results are out, the levels are compared with reference values to determine if the parameter is too low or too high.

What is normal LFT level?

Typical reference values are as follows

NB: These are for adult males, the values vary for females and young kids.

Note: Check out reference values of other tests here

These results are typical for adult men. Normal results vary from laboratory to laboratory and might be slightly different for women and children.

Your doctor will use these results to help diagnose your condition or determine the treatment you might need. If you already have liver disease, liver function tests can help determine how your illness is progressing and if you’re responding to treatment.

Where can I get my Liver function test in Kenya?

LFTs can be done in any level 5 and 6 public hospital. Most level 4 -6 private hospitals offer the test in their menu. Standalone laboratories like Metropolis, Pathcare and Lancet, among others, offer the tests in major urban areas.

You can get information about the nearest laboratory from our directory here

How much do Liver function tests cost?

As with most laboratory tests, there’s wide variation in costs across regions and types of facilities. The cost will also depend on how many of the components of the tests are ordered. In most instances, the cost will range from Kes 2200.00 to 4000.00

It’s prudent to research the precise, our laboratory price survey can help.

Related Tests

That’s A Wrap

Liver function tests are a group of laboratory tests employed to diagnose, evaluate and monitor many conditions including liver conditions, drugs and toxins as well as coagulation disorders. 

Consultation with a healthcare provider is essential for the accurate interpretation of test results in the proper context. 

See you in the next post, till then, happy and healthy living! 

Medically reviewed by Dr Mwaura J.