Narasi.net – Liver function tests are blood tests to screen or diagnose liver disorders. This test measures changes in the levels of enzymes released by the liver in response to damage or disease.
Check out the full explanation below.
What is a liver function test?
The liver is a vital organ in the human body that plays an important role in the digestive system, metabolism, and immunity.
Liver function tests include a series of blood tests to help diagnose and monitor liver disorders.
Several parts of this test can measure how well the liver is performing its functions, such as producing protein and cleaning the blood.
Liver function tests may be recommended by your doctor if you experience any of the following conditions.
- Experiencing damage from liver infections, such as hepatitis.
- Know the side effects of certain medications that affect liver function.
- Monitor the progress of liver disease and assess how well treatment is working.
- Have a medical condition related to the liver, such as high triglycerides, anemia, high blood pressure, or diabetes.
- Experiencing symptoms of liver disorders.
- Have gallbladder disease.
- Have a habit of drinking excessive alcohol.
What are the common tests for liver function tests?
Liver function tests consist of six separate tests performed from a single blood sample.
The doctor will check the levels of certain enzymes or proteins in the blood. Higher, lower, or normal levels can indicate certain liver problems.
The most common set of enzymes are checked through liver function tests such as the following.
1. Alanine aminotransferase (ALT)
Alanine aminotransferase (ALT) is an enzyme that helps convert protein into energy for liver cells.
This enzyme is generally found in the liver, but can also be found in the bloodstream in fairly low levels.
When liver damage occurs, the ALT enzyme can leak into the blood vessels. This condition can be triggered by viral hepatitis or alcoholic hepatitis.
In addition, shock or toxicity of certain drugs can increase ALT levels in the blood. Even so, inflammation or death of liver cells can only be known through a liver biopsy.
ALT examination through a blood sample cannot be used to diagnose liver damage or disease.
2. Aspartate aminotransferase (AST)
Aspartate aminotransferase (AST) is a mitochondrial enzyme found in the heart, liver, muscles, kidneys, and brain.
As with ALT, levels of the enzyme AST are normally present at low levels in the blood.
The AST enzyme which functions to help metabolize this amino acid will be released in excess into the blood when liver damage occurs.
In most cases of liver disorders, the levels of ALT and AST enzymes will increase in almost the same ratio
3. Alkaline phosphatase (ALP)
Alkaline phosphatase (ALP) is an enzyme that is present in many tissues of the human body, including the intestines, kidneys, placenta, and bones.
Enzymes that play an important role in breaking down this protein are produced in the bile ducts and sinusoidal membranes of the liver.
If the bile duct is blocked, ALP levels will increase. In addition, levels of this enzyme will increase if there is cirrhosis, sclerosing cholangitis, and liver cancer.
Other health problems, such as bone disease, congestive heart failure, and hyperthyroidism can also cause unexpectedly high ALP levels.
Meanwhile, ALP levels can be caused by liver problems if levels of the enzyme gamma-glutamyl transferase (GGT) are also elevated.
Bilirubin is a yellow liquid that is produced in the liver from dead red blood cells.
Liver disease can increase the level of bilirubin in the blood. If organs are damaged, bilirubin can leak into the bloodstream and cause jaundice (jaundice).
This condition shows symptoms, including yellowing of the eyes and skin, dark urine, and lighter colored stools.
Various causes of increased levels of bilirubin, such as viral hepatitis, liver cirrhosis, or blockage of the bile ducts.
The bilirubin test as part of a liver function test measures the amount of bilirubin in the blood vessels.
Meanwhile, the direct bilirubin test will measure the amount of bilirubin produced in the liver.
Albumin is a protein produced by the liver and is most abundant in the bloodstream. The albumin test measures how well the liver is producing this protein.
Test results showing low albumin levels can indicate a serious liver disorder.
Malnutrition, kidney disease, infection, and inflammation can cause albumin levels to drop in your bloodstream.
Low levels of albumin can reduce the pressure that carries fluid into the bloodstream. This condition can cause swelling in the ankles and soles of the feet.
6. Total protein (TP)
Total protein (TP) is a part of a liver function test that measures albumin and all other proteins in the bloodstream, including antibodies that help fight infection.
Many different things cause an abnormal increase or decrease in protein.
A number of these conditions, including liver disease, kidney disease, blood cancer, malnutrition, or abnormal swelling of the body.
Preparation before liver function test
Before undergoing the examination, the doctor will give instructions regarding this procedure.
Certain foods or medications can affect the levels of enzymes and proteins in the blood.
Doctors will generally ask you to avoid consuming these foods or drugs for some time before taking the blood sample.
Even so, make sure you still drink enough water before the examination.
Make sure to wear comfortable clothes when you go to the hospital. You may need to wear a top that makes it easier to collect a blood sample from your arm.
Liver function test procedure
If you’ve had other tests that involve drawing blood, you’re probably familiar with this procedure.
The first time, the medic will clean the skin at the injection site. This is to reduce the possibility of microorganisms causing infection.
An elastic band will wrap around the arm to help medics see the blood vessels more clearly.
The medic will draw blood through a vein in the crease of your arm. Then, the blood will be taken according to the amount needed for the examination.
If the amount of blood sample is sufficient, the medical officer will remove the needle and put gauze at the injection site.
The blood sample that has been collected in the tube will then be examined in the laboratory for deeper analysis results.
Things after having liver function test
Broadly speaking, the process of checking liver function does not take long. Your doctor will let you go home immediately after this procedure.
If you have certain health conditions or feel dizzy after having a blood test, it’s best to get some rest before leaving the hospital.
Make sure your body condition has recovered beforehand when you return home.
What are the results of liver function tests?
Liver function tests can help doctors determine liver health problems, as well as make a proper diagnosis and treatment plan.
Quoted from the Mayo Clinic, the results of normal liver function tests are as follows.
- ALT: 7 – 55 IU/L (units per liter)
- AST: 8 – 48 IU/L
- ALP: 40 – 129 IU/L
- Bilirubin: 0.1 – 1.2 mg/dl (milligrams per deciliter)
- Albumin: 3.5 – 5.0 mg/dl
- Total protein: 6.3 – 7.9 mg/dl
These results generally apply to adult men. However, normal results may vary and may vary slightly for adult women and children.
Doctors will use the results of these tests to help diagnose the condition and determine the appropriate treatment.
However, if you already have liver disease, liver function tests will help track progress and assess the response to treatment.
If you have any questions about this examination, please consult your doctor for more information.