A bilirubin test measures the amount of bilirubin in a blood sample. Bilirubin is a brownish yellow substance found in bile. It is produced when the liver breaks down old red blood cells. Bilirubin is then removed from the body through the stool (feces) and gives stool its normal colour.
Bilirubin circulates in the bloodstream in two forms:
Total bilirubin and direct bilirubin levels are measured directly in the blood, whereas indirect bilirubin levels are derived from the total and direct bilirubin measurements.
When bilirubin levels are high, the skin and whites of the eyes may appear yellow (jaundice). Jaundice may be caused by liver disease (hepatitis), blood disorders (hemolytic anemia), or blockage of the tubes (bile ducts) that allow bile to pass from the liver to the small intestine.
Mild jaundice in newborns usually does not cause problems. But too much bilirubin (hyperbilirubinemia) in a newborn baby can cause brain damage (kernicterus) and other serious problems. So some babies who develop jaundice may need treatment to lower their bilirubin levels.
The bilirubin test is used to:
Adults should not eat or drink for 4 hours before a bilirubin test.
No special preparation is needed for children before having a bilirubin test.
Tell your doctor if you:
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).
For a heel stick blood sample, several drops of blood are collected from the heel of your baby. The skin of the heel is first cleaned with alcohol and then punctured with a small sterile lancet. Several drops of blood are collected in a small tube. When enough blood has been collected, a gauze pad or cotton ball is placed over the puncture site. Pressure is maintained on the puncture site briefly, and then a small bandage is usually applied.
Instead of the standard heel stick, some hospitals may use a device called a transcutaneous bilirubin metre to check a newborn's bilirubin level. This small hand-held device measures bilirubin levels when it is placed gently against the skin. With this device, there may be no need to puncture the baby's skin. This is a screening test, and a blood sample will be needed if your baby's bilirubin level is high.
The health professional taking a sample of your blood will:
A brief pain, like a sting or a pinch, is usually felt when the lancet punctures the skin. Your baby may feel a little discomfort with the skin puncture.
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
There is very little chance of a problem from a heel stick. A small bruise may develop at the site.
There is very little chance of a problem from having a blood sample taken from a vein.
A bilirubin test measures the amount of bilirubin in a blood sample. The results are usually available in 1 to 2 hours.
The normal values listed here-called a reference range-are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
0.0–1.4 mg/dL or 1.7–20.5 mcmol/L
0.0–0.3 mg/dL or 1.7–5.1 mcmol/L
0.2–1.2 mg/dL or 3.4–20.5 mcmol/L
Low levels of bilirubin in the blood may be caused by:
Normal values in newborns depend on the age of the baby in hours and whether the baby was premature or full term. Normal values may vary from lab to lab.
Reasons you may not be able to have the test or why the results may not be helpful (except in newborns) include:
Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.
Other Works Consulted
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
ByHealthwise StaffPrimary Medical ReviewerE. Gregory Thompson, MD - Internal MedicineBrian D. O'Brien, MD - Internal MedicineAdam Husney, MD - Family MedicineSpecialist Medical ReviewerW. Thomas London, MD - Hepatology
Current as ofOctober 14, 2016
Current as of: October 14, 2016
E. Gregory Thompson, MD - Internal Medicine
& Brian D. O'Brien, MD - Internal Medicine & Adam Husney, MD - Family Medicine & W. Thomas London, MD - Hepatology
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