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Bilirubin, Serum/Plasma — Mass Concentration

Published: August 9, 2026Updated: August 16, 2026

This blood test measures bilirubin, a yellow pigment made when the body breaks down red blood cells. It helps evaluate the liver, bile ducts, and rate of blood-cell breakdown.

Quick summary

["Abnormal bilirubin levels can reflect liver or bile-duct problems or increased red blood cell breakdown."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
110942-0
Short code
Bilirub Msmt Amn
Synonyms
Bilirub Msmt Amn
Category
liver
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What is this test?

A bilirubin test measures the amount of bilirubin in blood. Bilirubin is produced as the body breaks down old red blood cells and is processed by the liver before being removed from the body.

Why might I need this test?

This test may be ordered as part of a liver panel, to evaluate jaundice, or to monitor known liver disease. It can also help assess conditions that cause increased red blood cell breakdown.

How is the test performed?

A blood sample is collected from a vein, usually in the arm. The laboratory measures bilirubin in the serum or plasma using a standardized chemical method.

How do I prepare for the test?

Fasting is usually not required for a bilirubin test by itself. If it is part of a broader liver or metabolic panel, follow any fasting or medication instructions provided by your clinician.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated bilirubin result may indicate liver-cell injury, impaired bile processing, or a blockage in the bile ducts. Increased bilirubin can also result from faster red blood cell breakdown, such as in hemolytic anemia. The result should be interpreted with other laboratory findings, symptoms, and your medical history.

Short name

Bilirubin

Frequently asked questions

What does a bilirubin blood test measure?
It measures bilirubin in blood, a pigment formed during the breakdown of red blood cells and removed by the liver.
What can cause bilirubin levels to be high?
Common causes include liver disease, bile-duct blockage, and increased red blood cell breakdown. Your clinician will interpret the result alongside the rest of your blood tests.
Does this test require fasting?
Fasting is generally unnecessary unless the bilirubin test is being performed with another panel that requires it. Follow the preparation instructions given with your lab order.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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