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Direct Bilirubin, Whole Blood — Mass Concentration

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

Measures the amount of direct bilirubin in blood, helping evaluate liver function and possible blockage of bile flow.

Quick summary

["An elevated direct bilirubin result may indicate impaired bile flow or certain liver conditions."]

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

Key facts at a glance

LOINC
48623-3
Short code
Bilirub Direct BldCo-mCnc
Synonyms
Bilirub Direct BldCo-mCnc
Category
liver
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

Direct bilirubin is the part of bilirubin that reacts directly with the laboratory's test reagent. It mainly reflects bilirubin that has been processed by the liver and is ready to be excreted in bile.

Why might I need this test?

This test may be ordered to evaluate jaundice, unexplained changes in liver-related blood tests, or symptoms suggesting a bile duct problem. It is often interpreted with total bilirubin and other liver tests.

How is the test performed?

A laboratory analyzes a blood sample and measures the concentration of direct bilirubin. The result is reported as the amount of bilirubin per unit volume of blood.

How do I prepare for the test?

Special preparation is usually not required for this test. Follow any instructions from your healthcare professional, and fast only if your clinician or the laboratory specifically requests it.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Direct bilirubin

Frequently asked questions

What is the difference between direct and total bilirubin?
Total bilirubin includes all bilirubin in the blood, while direct bilirubin measures the fraction that reacts directly with the test reagent. Direct bilirubin is mainly associated with bilirubin that the liver has processed for excretion.
Does a high direct bilirubin level mean I have a bile duct blockage?
Not necessarily. A blockage is one possible cause, but other liver conditions and certain medications can also raise direct bilirubin. Your clinician will interpret the result with your symptoms and other laboratory findings.
Is fasting required for a direct bilirubin test?
Fasting is usually not required, although eating can affect bilirubin measurements. Follow the preparation instructions provided by the laboratory or your healthcare professional.
  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