Bilirubin
Bilirubin is a yellow pigment produced by the breakdown of hemoglobin in red blood cells. It is present in blood in two main forms: unconjugated (or indirect) bilirubin and conjugated (direct) bilirubin.
Unconjugated bilirubin doesn't dissolve in water. In the liver, it is conjugated (bound) to glucuronic acid to make it water-soluble. Conjugated bilirubin is then excreted through the bile ducts into the intestine. Some bilirubin is eliminated in the stool, while the rest is reabsorbed by the intestine.
Blood bilirubin level therefore depends on liver, gallbladder and bile ducts health. It also informs us about the destruction of red blood cells.
Unconjugated bilirubin (indirect) is measured indirectly by subtracting the value of conjugated bilirubin (direct) from the total amount of bilirubin in your blood.
| What is the purpose of this test? |
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| How to prepare? |
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| Reference values* |
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| Associated tests | Related tests include the following:
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| How is it done? | A blood sample is drawn, usually from a vein in the arm. |
| How long before I get the results? | Results are usually ready in a day. It may take longer to receive your results. |
What does an abnormal test result mean?
High bilirubin values:
- Liver damage (e.g., cirrhosis, hepatitis, mononucleosis, drug side effects, alcohol abuse)
- Certain types of anemia (e.g., sickle cell, hemolytic)
- Adverse reaction following a blood transfusion
- Bile duct damage (e.g., bile duct obstruction)
- Liver damage (e.g., cirrhosis, hepatitis)
- Hereditary disease (e.g., Gilbert's or Rotor syndrome)
Medications that may affect test results
Certain medications may affect test results. Here are a few examples:
- Contraceptives containing estrogen
- Diazepam
- Vitamin C
- Acetaminophen
- Theophylline
- Certain HIV medications
What you should know before going for this test
When you go in for a blood test or any other medical exam, it's always a good idea to bring a complete list of any prescriptions, over-the-counter medications, or natural health products you're taking. Unless otherwise advised, it's best to take your medications as usual on blood test days. If in doubt, don't hesitate to talk to your healthcare professional.
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The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.