Bilirubin, Serum/Plasma — Substance Concentration
Measures the amount of bilirubin in serum or plasma to help evaluate liver function, bile duct obstruction, and conditions causing increased breakdown of red blood cells.
["This blood test measures bilirubin to help assess liver function and identify causes of yellowing of the skin or eyes."]
Key facts at a glance
- LOINC
- 14631-6
- Short code
- Bilirub SerPl-sCnc
- Synonyms
- Bilirub SerPl-sCnc
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
A bilirubin test measures bilirubin, a yellow pigment made when the body breaks down old red blood cells. The test is performed on a blood sample and may measure total bilirubin or both direct and indirect bilirubin.
Why might I need this test?
Doctors may order this test as part of a liver panel or when someone has jaundice, dark urine, pale stools, itching, or unexplained fatigue. It can help evaluate liver function, gallbladder or bile duct problems, and increased blood cell breakdown.
How is the test performed?
A healthcare professional draws a small amount of blood from a vein and sends it to a laboratory. The laboratory measures the bilirubin concentration in the serum or plasma using a validated testing method.
How do I prepare for the test?
Fasting is usually not required for a bilirubin test by itself, but it may be part of a larger panel that includes fasting instructions. Tell your healthcare professional about medicines, supplements, pregnancy, or recent blood transfusions, and follow the specific instructions provided by the laboratory.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A higher bilirubin level may indicate that the liver is not processing bilirubin normally, that bile flow is blocked, or that red blood cells are being destroyed more quickly than usual. The pattern of direct and indirect bilirubin, along with other laboratory findings and symptoms, helps doctors determine the likely cause.
Bilirubin levels should be interpreted by a healthcare professional because factors such as medicines, recent illness, pregnancy, and laboratory methods can affect the result. An isolated abnormal result does not by itself establish a diagnosis.
Short name
Bilirubin
Frequently asked questions
What does a bilirubin blood test measure?
What can cause bilirubin levels to be high?
Do I need to fast before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy