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Bilirubin, Spectrophotometry — Substance Concentration

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

This test measures bilirubin, a pigment produced when the body breaks down heme, and may be used to evaluate the liver, bile ducts, or red blood cell breakdown.

Quick summary

["Abnormal bilirubin levels can reflect liver disease, bile duct blockage, or increased red blood cell breakdown."]

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

Key facts at a glance

LOINC
32303-0
Short code
Bilirub Spec-sCnc
Synonyms
Bilirub Spec-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?

This test measures the amount of bilirubin in a blood sample. Bilirubin is a yellow pigment made when the body breaks down heme, the oxygen-carrying part of red blood cells.

Why might I need this test?

A bilirubin test may be ordered as part of a liver panel or to investigate jaundice, which can cause yellowing of the skin or eyes. It can also help evaluate bile duct problems or increased red blood cell breakdown.

How is the test performed?

A blood sample is collected and analyzed in the laboratory using a spectrophotometric method, which measures how much light the sample absorbs to determine the bilirubin concentration.

How do I prepare for the test?

Fasting is usually not required for a bilirubin test unless your healthcare professional gives different instructions. Tell the laboratory if you are pregnant or taking medications that may affect liver function or bilirubin levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Bilirubin test

Frequently asked questions

What does bilirubin measure?
Bilirubin is a pigment produced during the breakdown of heme from red blood cells. Measuring it helps evaluate red blood cell turnover, liver function, and bile flow.
Why does an abnormal bilirubin level matter?
An elevated level may occur with liver disease, bile duct blockage, or increased red blood cell breakdown. It may also contribute to jaundice.
Do I need to fast before this test?
Fasting is generally unnecessary, but follow any instructions from your healthcare professional. The test may be ordered with other liver tests, some of which have different preparation requirements.
  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