Bilirubin

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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?	To monitor and detect liver disorders (e.g., hepatitis, cirrhosis, drug side effects) To detect hemolytic anemia (destruction of red blood cells) or genetic diseases in babies To identify gallbladder or bile duct disorders such as a bile duct obstruction (e.g., gallstones, pancreatic tumours)
How to prepare?	Dietary restrictions are usually not required. In some cases, you may be asked to fast for 4 hours before the test.
Reference values*	Total bilirubin: 3-17 mcmol/L Direct bilirubin (conjugated): 2-9 mcmol/L
Associated tests	Related tests include the following: Liver function tests, which measure, among other substances: albumin, alkaline phosphatase (ALP), ALT, AST, gamma-glutamyl transferase (GGT), and lactate dehydrogenase (LDH). A complete blood count may also be requested.
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.

* These values are presented for information purposes only. As different laboratories may have different target values, the lab report usually specifies the values used for the test. It should also be noted that test results must be interpreted based on factors such as age, sex, and health condition. Values outside of this range may be considered normal for some individuals.

What does an abnormal test result mean?

High bilirubin values:

Total bilirubin:

Liver damage (e.g., cirrhosis, hepatitis, mononucleosis, drug side effects, alcohol abuse)

Unconjugated bilirubin (indirect):

Certain types of anemia (e.g., sickle cell, hemolytic)
Adverse reaction following a blood transfusion

Conjugated bilirubin (direct):

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.