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Unconjugated Bilirubin (Serum)

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

This test measures the amount of bilirubin in your blood after it has been released from broken red blood cells. Bilirubin is a yellow pigment produced when your body breaks down old red blood cells.

Quick summary

["Bilirubin helps your liver process waste and helps prevent anemia-related damage."]

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

Key facts at a glance

LOINC
98610-9
Short code
SNAP area AUC L radial n
Synonyms
SNAP area AUC L radial n
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nerve-conduction
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 This Test Is Done

Your doctor may order this test to check for liver disease, bile duct blockages, or conditions like hemolytic anemia, where red blood cells break down faster than usual. It can also help diagnose jaundice, especially in newborns, or monitor treatment effectiveness.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein in your arm to draw blood. If you’re a newborn, the test might be done through a heel prick. Tell your doctor about any medications or supplements you’re taking, as they could affect results.

What the Test Results Mean

High bilirubin levels may indicate liver problems, poor liver function, or conditions like hepatitis or cirrhosis. Very high levels can cause jaundice (yellowing of skin and eyes). Low levels might suggest anemia or other blood disorders. Your doctor will interpret results in the context of your overall health.

Common Conditions Monitored

This test is often used to monitor jaundice in newborns, evaluate liver function, diagnose bile duct issues, or track conditions like Gilbert’s syndrome, Crigler-Najjar syndrome, or hemolytic anemia.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Bilirubin, Total (Serum)

Frequently asked questions

What causes elevated bilirubin levels?
Elevated bilirubin can result from overproduction (e.g., hemolysis), impaired liver processing, or blocked bile flow. In newborns, high bilirubin may require phototherapy to prevent brain damage.
How often should I get this test?
Frequency depends on your health condition. Doctors may order it periodically for chronic liver disease, regularly for jaundiced newborns, or after trauma/injury to assess red blood cell breakdown.
Does diet affect bilirubin levels?
Dietary changes alone won’t alter bilirubin levels, but certain foods (e.g., high-fiber or vitamin K-rich foods) may indirectly support liver function. Always follow your doctor’s guidance.
  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