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Metabolic dysfunction-associated fatty liver disease or MAFLD is a condition in which your body stores a lot of fat in your liver. This is due to ongoing health issues such as obesity, diabetes and high blood pressure. Previously known as non-alcoholic fatty liver disease (NAFLD), the term MAFLD was introduced to better reflect the underlying cause.
Over time, excess fat in your liver can causes inflammation and damage. This can eventually lead to scar tissue forming in your liver which is called fibrosis. When fibrosis becomes severe and the liver cannot function properly, this is cirrhosis. Early diagnosis and treatment can help stop MAFLD from getting worse.
In assessing the health of your liver, it is important to find out if there is any fibrosis and if so, how severe it is. The amount of fibrosis is important in deciding on treatment and management and whether you should go on to see a liver specialist (hepatologist) for closer investigation.
The best way to investigate fibrosis has been through a liver biopsy in which small samples of tissue are taken from your liver through a surgical procedure. However, biopsies are invasive, uncomfortable and there is a risk of complications.
In recent years, less-invasive ways of assessing scarring have been developed and trialled. One of these is the FIB-4, a non-commercial test recommended by the Gastroenterological Society of Australia (GESA) for the diagnosis and management of MAFLD.
If your doctor suspects you may have MAFLD they will order some standard blood tests such as Liver Function Tests (LFTs), a panel of tests used to check the health of your liver, a Full Blood Count (FBC), a very common test used to check the components of your blood, and the lipid panel, which looks at the fats in your blood including cholesterol. They may arrange for you to have a liver ultrasound.
They may order the FIB-4 test to check for liver fibrosis. This test takes the results of three tests together with your age and calculates the likelihood and extent of fibrosis. It gives you a score – the higher the score the higher the likelihood of fibrosis.
The FIB-4 test uses the results of AST and ALT which are normally done as part of Liver Function Tests (LFTs) and the platelet count which is done as part of the Full Blood Count (FBC).
Aspartate aminotransferase is an enzyme that is found mainly in the liver but also in the heart, red blood cells and other muscles. If your liver, red blood cells, heart or muscle cells are damaged or inflamed they release AST into the blood. High levels of AST in the blood suggests you might have damaged cells or inflammation somewhere in your body, but it cannot indicate where this damage is in the body.
Alanine aminotransferase is an enzyme mainly found in your liver. When liver cells are damaged ALT is released into your blood. High ALT suggests there is damage in your liver.
Platelets are tiny plate-shaped cells that circulate in your blood. They bind together to form clots when blood vessels are injured. Platelet levels are influenced by liver disease. When the liver is damaged, platelets may become trapped in the enlarged liver, leading to fewer platelets circulating in the blood. A lower platelet count can suggest advanced liver fibrosis. It can also be a sign of portal hypertension, a condition in which blood flow through the liver is blocked causing high blood pressure.
Why is the FIB-4 normally only suitable for MAFLD?
In order to make sure your FIB-4 test results are accurate you may be asked to have several other tests to help with interpretation. You may have tests for:
Some of these conditions can affect the results of AST, ALT and platelets. For example, heavy drinking can cause AST levels to rise significantly even if there is no fibrosis. Alcohol can also affect AST/ALT ratios and platelet counts, while muscle injury can affect AST levels, and blood disorders can affect the platelet count.
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FIB-4 is a calculation that uses a patient age and the results from the AST, ALT and platelet count blood tests.
FIB-4 = {Age (years) x AST (U/L) } / {platelet count (x10^9) x √ALT (U/L)}
| If you have MAFLD, the following are recommended: | ||
| Score | Interpretation | Next step |
| Less than 1.3 | Low risk of liver fibrosis. | Repeat testing in 3 years. |
| 1.3 – 2.7 | Intermediate risk of liver fibrosis. | You may need further investigation of your liver. This may be done with a liver elastogram (a type of imaging of your liver) or direct serum tests* such as the Enhanced Liver Fibrosis (ELF) or Hepascore tests. These are especially useful if results are unclear. |
| More than 2.7 | High risk for advanced fibrosis. | You will be referred to a liver specialist. |
| *Direct serum fibrosis tests such as the Enhanced Liver Fibrosis (ELF) and Hepascore can more directly reflect the degree of liver fibrosis in chronic liver disease. It is important to note that these tests are not specific to liver fibrosis and can also reflect other chronic fibrotic diseases. They are privately billed tests and not rebated by the MBS. | ||
The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.
You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.
Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:
Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.
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