Contributed by – Healthians Team
What is the Bilirubin Serum test?
Bilirubin blood test measures the levels of bilirubin — an orange-yellow pigment — in your blood. Bilirubin is produced as a result of the ordinary breakdown of haemoglobin from worn out red blood cells. This degradation of RBCs is a normal and healthy process. After circulating in the blood, bilirubin passes through the liver and is ultimately discharged from the body through stool (which is why stool has the brown colour that it does).
There are two types of bilirubin that can be estimated by a blood test: conjugated (direct) and unconjugated (indirect). Total bilirubin is the sum of direct and indirect bilirubin in the body. Your bilirubin serum test results come back with both a total and direct value. Indirect bilirubin is calculated by subtracting direct bilirubin from the total: indirect serum bilirubin = total serum bilirubin − direct serum bilirubin.
Conjugated bilirubin depicts that sugar has been attached to it. Direct bilirubin is associated with the liver and the higher the level, the more severe is the liver damage. This form of bilirubin is water-soluble.
Unconjugated bilirubin depicts the absence of sugar. Indirect bilirubin is not always associated with liver damage and can be high in non-liver conditions also. This form of bilirubin is not water-soluble.
Who should get a Bilirubin Serum test?
The bilirubin test is an important part of routine new-born diagnostic screening tests to determine if the circulating level of bilirubin is normal or abnormal.
You may need this test if you have signs or symptoms of liver damage or disease. Symptoms include:
- Yellowish skin or eyes (jaundice)
- Stomach pain
- Nausea/Vomiting
- Abdominal pain
- Dark amber-coloured urine
- Light-colored stool
- Flu-like symptoms, such as fever and chills
- Fatigue and general malaise
You may also require your bilirubin level tested regularly if you are being treated for liver disease.
Why is the Bilirubin Serum test needed?
Bilirubin testing may be used for a variety of reasons. In new-borns, it is done to monitor neonatal jaundice. In the case of adults and older children, bilirubin blood testing is typically done as a part of a panel of tests to check the soundness of your liver. It may be also done to evaluate other condition/s that may be present. The Bilirubin Total is needed in case of:
- Signs or symptoms of liver disease such as dark-coloured urine, jaundice, nausea, vomiting, abdominal pain, fatigue
- History of taking heavy intake of alcohol
- In case of exposure to the hepatitis virus
- Symptoms of hemolytic anemia
What does a Bilirubin Serum test result mean?
All individuals produce bilirubin on a daily basis as part of the normal turnover of red cells. A small amount of bilirubin in the blood is normal.
Many laboratories consider the normal range for total blood bilirubin as below:
Direct bilirubin: 0 to 0.3 mg/dL
Total bilirubin: 0.3 to 1.9 mg/dL
Note: mg/dL = milligrams per decilitre
Lower than normal results
Lower than normal bilirubin levels are usually not a concern and do not require to be monitored
Higher than normal results
Higher than normal levels of bilirubin may indicate that your liver isn’t clearing bilirubin properly, suggesting that liver function problems or other abnormalities may be present. Occasionally, elevated bilirubin levels may be caused by an increased rate of red blood cell destruction (hemolysis) and transfusion reactions.
How is the Bilirubin Serum test done?
Bilirubin testing is done by taking a blood sample from the bend of your arm. In new-borns, blood draws are sometimes done as a heel stick collection.
You may be required to avoid eating or drinking for at least 4 hours before the test. Some drugs can change the bilirubin levels in your blood. Your health care provider may instruct you to stop taking medications that affect the test.
