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Direct Bilirubin, Plasma — Mass Concentration

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

Measures direct bilirubin in plasma. Direct bilirubin is the fraction primarily processed by the liver and is used to help evaluate liver function and jaundice.

Quick summary

["An elevated direct bilirubin level may indicate impaired bile processing or liver disease."]

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

Key facts at a glance

LOINC
56905-3
Short code
Bilirub Direct Plr-mCnc
Synonyms
Bilirub Direct Plr-mCnc
Category
liver
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What is this test?

This blood test measures direct bilirubin, also called conjugated bilirubin, in plasma. Bilirubin is a yellow pigment produced as the body breaks down red blood cells.

Why might I need this test?

Your clinician may order this test to help evaluate jaundice, unexplained yellowing of the skin or eyes, or suspected liver and bile duct problems. It is often interpreted with total bilirubin and other liver tests.

How is the test performed?

A blood sample is collected, usually from a vein, and sent to a laboratory. The laboratory measures the amount of direct bilirubin in the plasma and may report it as a mass concentration.

How do I prepare for the test?

Fasting is usually not required for this test, but follow your clinician's instructions. Tell the healthcare team if you have recently taken a medication that affects liver function or bilirubin levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Direct Bilirubin

Frequently asked questions

What is direct bilirubin?
Direct bilirubin is the fraction of bilirubin that has been processed by the liver and is ready to be excreted in bile.
Does a high direct bilirubin level always mean the liver is damaged?
No. It may reflect liver dysfunction, impaired bile flow, or other conditions, so your clinician will interpret it alongside symptoms and other test results.
Is fasting required for this blood test?
Fasting is generally not required, but medication use, recent illness, and laboratory preparation instructions should be discussed with your clinician.
  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