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Serum or plasma concentration of bilirubin (total)

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

["Total bilirubin helps diagnose liver or bile problems and monitor conditions like jaundice."]

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

Key facts at a glance

LOINC
33399-7
Short code
N men sg B+E coli K1 Ag Ser Ql
Synonyms
N men sg B+E coli K1 Ag Ser Ql
Category
chemistry
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

Why This Test Matters

Bilirubin is a byproduct of red blood cell breakdown. When your liver processes it, it should be excreted through bile into your intestines. If bilirubin builds up in your blood, it can cause yellowing of the skin and eyes (jaundice). High levels may signal liver disease, gallbladder issues, or other health concerns.

What to Expect Before the Test

No special preparation is needed. You may have a blood draw from a vein in your arm. If you’re tested for urine bilirubin (not applicable here), you might be asked to collect a urine sample in a container.

Possible Causes of Abnormal Results

Elevated bilirubin can result from liver diseases (like hepatitis), blockages in the bile ducts, hemolytic anemia (rapid red blood cell destruction), or certain medications. Low levels are less common but may occur with liver damage or certain genetic conditions.

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL). While exact ranges vary by lab, high values (above normal) may prompt further testing to explore underlying causes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Total bilirubin

Frequently asked questions

Could I have jaundice if my bilirubin is high?
Yes, high bilirubin often causes jaundice, especially if it builds up in your bloodstream. Your doctor may recommend additional tests to determine the cause, such as liver function tests or imaging.
What if my bilirubin is high but I don’t have symptoms?
Even without visible jaundice, high bilirubin can indicate an issue like a bile duct blockage or liver disease. Your doctor will discuss next steps, which may include more tests or monitoring.
Why would my bilirubin be low?
Low bilirubin is less common but may occur with severe liver damage or certain genetic disorders. Your doctor will review your medical history and other test results to understand the reason.
  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