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Bilirubin Fractions Panel, Serum/Plasma — Substance Concentration

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

Measures total bilirubin and its direct and indirect fractions in serum or plasma to help evaluate causes of jaundice.

Quick summary

["This test helps determine whether elevated bilirubin is mainly direct or indirect."]

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

Key facts at a glance

LOINC
75697-3
Short code
Bilirubin fractions Pnl SerPl-sCnc
Synonyms
Bilirubin fractions Pnl SerPl-sCnc
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?

A bilirubin fractions panel measures the amount of bilirubin in your blood and separates it into direct and indirect fractions. Direct bilirubin is conjugated by the liver, while indirect bilirubin has not yet been conjugated.

Why might I need this test?

Your clinician may order this test to investigate jaundice, yellowing of the skin or eyes, dark urine, or pale stools. It can help distinguish liver and bile duct problems from increased breakdown of red blood cells.

How is the test performed?

A blood sample is collected, usually by drawing blood from a vein. The laboratory measures bilirubin in the serum or plasma and reports the total amount and the direct and indirect fractions.

How do I prepare for the test?

Fasting is usually not required, but follow any instructions from your clinician. Tell the healthcare professional if you are pregnant or breastfeeding, because pregnancy can affect bilirubin levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated direct bilirubin fraction may indicate impaired bile processing or a liver or bile duct disorder. An elevated indirect fraction may result from increased red blood cell breakdown, reduced liver uptake, or impaired conjugation, depending on the clinical context. Results should be interpreted with symptoms, medical history, and other liver or blood tests.

Short name

Bilirubin fractions

Frequently asked questions

What is the difference between direct and indirect bilirubin?
Direct bilirubin has been processed by the liver and is excreted in bile. Indirect bilirubin has not yet been processed by the liver and includes bilirubin released during normal or increased red blood cell breakdown.
Does this test diagnose a specific condition?
No. The results show how bilirubin is distributed and must be combined with your symptoms, examination, and other laboratory tests to identify the cause.
Do I need to fast before the test?
Fasting is generally not necessary for a bilirubin fractions panel. Follow your clinician's instructions, and tell the laboratory if you are pregnant or breastfeeding.
  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