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Bilirubin, Direct, Serum/Plasma — Mass Concentration

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

A blood test that measures direct bilirubin, a form of bilirubin processed by the liver, to help assess liver function and bile flow.

Quick summary

["Direct bilirubin helps evaluate liver function and may be elevated with liver injury or impaired bile flow."]

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

Key facts at a glance

LOINC
110110-4
Short code
Bilirub Direct Msmt SerPl
Synonyms
Bilirub Direct Msmt SerPl
Category
liver
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

What is this test?

Direct bilirubin measures the amount of bilirubin in blood that has been processed by the liver. Bilirubin is a yellow pigment produced when the body breaks down red blood cells, and the liver helps remove it from the bloodstream.

Why might I need this test?

This test may be ordered as part of a liver panel or to help evaluate jaundice, which can cause yellowing of the skin or eyes. It may also be used to assess conditions that affect the liver or the flow of bile.

How is the test performed?

A blood sample is collected from a vein, usually from the arm. The laboratory analyzes the sample using a method that specifically measures direct bilirubin.

How do I prepare for the test?

Fasting is usually not required for this test, unless your healthcare professional specifically says otherwise. Tell your clinician about medicines, supplements, pregnancy, or recent blood transfusions because these factors can affect bilirubin results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated direct bilirubin result may indicate impaired bile flow, such as from a blockage in the bile ducts, or may occur with liver inflammation or injury. Results should be interpreted with the rest of your liver tests, medical history, and examination because direct bilirubin can rise for several different reasons.

Short name

Direct bilirubin

Frequently asked questions

What is direct bilirubin?
Direct bilirubin is bilirubin that has been processed by the liver and is ready to be excreted in bile. It is measured as part of assessing liver function and jaundice.
Does a high direct bilirubin level mean I have liver disease?
Not necessarily. It can indicate liver injury or a problem with bile drainage, but other conditions and test results must also be considered. Your healthcare professional can explain the result in context.
Do I need to fast before this test?
Fasting is generally not needed unless your clinician has specifically requested it. Follow the preparation instructions provided with your lab order.
  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