» See MoreRobert got a call the same day asking him to come back to the doctor where he was told the results of his blood test indicated his liver wasn’t functioning properly. To find the cause, Robert needed an invasive liver biopsy, where a small sample of his liver was given to the pathology team. The results revealed autoimmune hepatitis.
Summary
What is bilirubin?
Bilirubin is an orange-yellow waste product that is made during the body's normal process of breaking down old red blood cells. It is processed by your liver and stored along with other waste products in a fluid called bile. If your liver is healthy, most of the bilirubin from your body is removed through your bile ducts, the tubes that carry bile from your liver. If your liver is damaged or your bile ducts are blocked, bilirubin can leak into your blood.
Bilirubin levels in the blood rise when either too much is being produced, or too little is being removed. High levels of bilirubin cause jaundice, in which your skin and the whites of your eyes become yellow.
Why get tested?
Bilirubin is typically measured as part of Liver Function Tests (LFTs). This is a standard group of tests that is routinely used to check the health of the liver.
LFTs measure enzymes and proteins that are either produced by the liver cells as part of its normal function or released into the blood when liver cells are damaged. Looked at together, along with your symptoms and medical history, they help build a picture of your liver’s health. Either higher or lower than normal levels of these substances can indicate a problem with your liver.
As well as bilirubin, they measure the enzymes gamma-glutamyl transferase (GGT), alanine transaminase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST) and albumin (the most common protein in your blood which is made by your liver).
Two types of bilirubin
A bilirubin test can help decide if your jaundice is due to a problem in your liver or a haemolytic disorder in which too many red blood cells are being broken down. This can be done by measuring two different forms of bilirubin, called conjugated (or direct) and unconjugated (or indirect) bilirubin.
When old red blood cells are broken down, they make unconjugated bilirubin, meaning it is not water-soluble and it is carried in your blood by being attached to the blood protein, albumin.
It travels to your liver where it is separated from the albumin, broken down and made water-soluble, becoming conjugated bilirubin.
Next, it passes into tiny ducts in the liver where it is picked up by bile, a thick green fluid that flows through a network of ducts inside your liver, and then it is transported to your gallbladder which sits under your liver. From there, it is released into your intestines eventually leaving your body in the faeces, giving the stool its characteristic brown colour.
| Type of bilirubin | Possible causes if levels are high |
| Unconjugated bilirubin | This indicates pre-liver causes such as a haemolysis (haemolytic disorder or the breakdown of too many red blood cells), ineffective making of red blood cells, or even impaired conjugation of bilirubin as seen in Gilbert syndrome. Since unconjugated bilirubin is not water-soluble, it doesn’t appear in urine. |
| Conjugated bilirubin | This suggests liver or post-liver problems, such as liver cell injury (like hepatitis), intra-liver blockages (cholestasis), or obstruction outside the liver (like gallstones or tumours compressing the biliary tree). Because conjugated bilirubin is water-soluble, it does show up in urine, often giving it a dark amber colour. |
Types of haemolytic disorders
Haemolytic anaemia
This is a disorder in which red blood cells are destroyed faster than they can be made. This can be inherited (such as with sickle cell anaemia and thalassemia) or acquired through a range of conditions such as infections, blood cancers, autoimmune disorders such as lupus, rheumatoid arthritis or ulcerative colitis, and as a reaction to some medications.
Haemolytic disease of the newborn
A condition known as haemolytic disease of the newborn is when a newborn’s red blood cells are being destroyed due to a blood incompatibility between the baby and mother.
Newborn or neonatal jaundice
Some babies are born with jaundice because their livers are not developed enough to remove excess bilirubin. It is not uncommon to see high bilirubin levels in babies typically two to seven days old. Newborn jaundice is usually not harmful and clears up within a few weeks. But in some cases, high bilirubin levels can lead to brain damage, so infants are often tested as a precaution. Newborn jaundice is likely to be of concern if it persists longer than 8 to 14 days and may be caused by abnormal metabolism in the liver (the liver not processing bilirubin correctly) or malformation of the bile ducts (the bile ducts not being formed correctly).
Although bilirubin may be toxic to brain development in newborns (up to the age of about two weeks), higher bilirubin levels in older children and adults do not pose the same threat. In older children and adults, the blood-brain barrier is more developed and prevents bilirubin from crossing into the brain cells. High bilirubin levels in children or adults, however, strongly suggest a medical condition that must be investigated and treated.
When levels of bilirubin are above a critical threshold, treatment such as phototherapy (where the baby is placed under special blue light that helps break down bilirubin in the skin, making it easier for the body to eliminate), blood exchange transfusion and medications can be used to reduce it.
Other conditions that affect bilirubin blood levels
Increases in bilirubin also may be due to metabolic problems, obstruction of the bile duct, infection, physical or chemical damage to the liver, or an inherited issue. Several inherited conditions including Gilbert’s syndrome, Dubin-Johnson syndrome, Rotor’s syndrome and Crigler-Najjar syndrome can cause a raised bilirubin level. Of these four syndromes, Crigler-Najjar is the most serious. The first three are usually mild, long-term conditions that can be aggravated under certain conditions but in general cause no significant health problems.
Having the test
Sample
Blood
Any preparation?
None
Your results
Reading your test report
Your results will be presented along with those of your other tests on the same form. You will see separate columns or lines for each of these tests.
An elevated bilirubin result indicates jaundice, and treatment will depend on the cause.
Reference intervals
Your results will be compared to reference intervals (sometimes called a normal range).
If your results are flagged as high this does not necessarily mean that anything is wrong. It depends on your personal situation. Your results need to be interpreted by your doctor.
| Bilirubin reference intervals | |
| Adult | 1 - 20 µmol/L |
| The reference intervals for this test are common reference intervals which means that most laboratories in Australia should be using this same target range. | |
Questions to ask your doctor
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:
More information
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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