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Serum or plasma concentration of total bilirubin

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

This test measures the 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

["Bilirubin levels can signal liver or bile flow issues."]

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

Key facts at a glance

LOINC
37819-0
Short code
XR tomo TMJ-R
Synonyms
XR tomo TMJ-R
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 bilirubin test to diagnose or monitor conditions affecting the liver, bile ducts, or red blood cells. It can also help identify signs of hemolytic anemia (when red blood cells break down too quickly) or liver diseases like hepatitis or cirrhosis.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein (usually in your arm) to draw blood. If you’re concerned about discomfort, let your healthcare provider know.

How the Results Are Interpreted

Bilirubin is divided into two types: direct (conjugated) and indirect (unconjugated). Results are often reported as total bilirubin levels, but direct/indirect splits can help pinpoint the cause of elevated levels.

Possible Causes of Abnormal Results

High bilirubin levels may indicate liver disease, bile duct problems, or red blood cell disorders. Low levels are less common but could suggest liver dysfunction or certain genetic conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Elevated bilirubin can signal jaundice (yellowing of skin/eyes), liver inflammation, or blockages in the bile flow. Low levels may rarely suggest liver damage or metabolic issues, but further testing is needed to confirm.

Short name

Bilirubin

Frequently asked questions

What does a high bilirubin level mean?
A high bilirubin level often means your liver or bile ducts aren’t working as they should, which can cause jaundice or other symptoms like dark urine or pale stools. Your doctor will discuss possible causes with you.
Can diet affect bilirubin test results?
Dietary changes rarely affect bilirubin levels, but certain foods (like high-fiber or cruciferous vegetables) might influence bile flow indirectly. Avoiding alcohol or medications that affect liver function before testing is best.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition. Regular monitoring may be needed if you have liver disease, bile duct issues, or other related conditions.
  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