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Serum or plasma concentration of total bilirubin

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

This test measures the total amount of bilirubin, a yellow pigment produced when red blood cells break down. It helps assess liver function and detect conditions like jaundice or bile duct blockages.

Quick summary

["Your bilirubin levels can signal liver or bile system issues."]

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

Key facts at a glance

LOINC
42437-4
Short code
XR tomo ST
Synonyms
XR tomo ST
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-tomography
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

Why Is This Test Done?

Doctors may order a total bilirubin test to diagnose or monitor conditions affecting the liver, bile ducts, or red blood cells. It can also help identify signs of jaundice (yellowing of the skin or eyes) or other liver-related problems.

What to Expect Before the Test

No special preparation is needed. If you’re having blood drawn, tell your healthcare provider about any medications or supplements you take, as they may affect results.

How the Test Works

Blood is drawn from a vein, usually in your arm. The sample is sent to a lab where bilirubin levels are measured using a method that detects its presence in the serum or plasma.

What the Results Mean

Higher than expected levels may indicate liver disease, hemolysis (red blood cell breakdown), or other conditions. Lower levels are less commonly significant unless part of a broader evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Elevated bilirubin often points to liver dysfunction, bile obstruction, or hemolytic anemia, while normal levels generally suggest healthy processing of bilirubin.

Short name

Total Bilirubin

Frequently asked questions

What causes elevated bilirubin?
Elevated bilirubin can result from liver diseases (like hepatitis), bile duct blockages, or conditions where red blood cells break down faster than the liver can process the pigment.
What if my bilirubin is high?
If your results are high, your doctor may recommend further tests (like liver function tests) or additional imaging to find the cause and guide treatment.
Does diet affect bilirubin levels?
Dietary factors like fiber, vitamin K, or certain medications may indirectly influence liver function, but they don’t directly alter bilirubin levels unless they cause liver stress.
  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