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Bilirubin, Plasma — Mass Concentration

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

Measures the amount of bilirubin in plasma to help evaluate liver function and identify conditions that cause increased red blood cell breakdown.

Quick summary

["Abnormal bilirubin levels may reflect liver disease or increased red blood cell breakdown."]

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

Key facts at a glance

LOINC
14421-2
Short code
Bilirub Plr-mCnc
Synonyms
Bilirub 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 test measures the concentration of bilirubin in plasma. Bilirubin is a yellow pigment produced during the normal breakdown of red blood cells and processed by the liver.

Why might I need this test?

Doctors may order this test as part of a liver panel or when symptoms suggest jaundice, liver disease, or excessive red blood cell breakdown. It may also be used to monitor certain medications or treatments.

How is the test performed?

A blood sample is drawn, and the plasma portion is analyzed to determine the bilirubin concentration. The test is often reported together with other liver-related measurements.

How do I prepare for the test?

Fasting is usually not required for an isolated bilirubin test, but follow any instructions provided with a liver panel or other scheduled tests. Tell your healthcare professional if you are pregnant or taking medications that may affect liver function.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Plasma Bilirubin

Frequently asked questions

What does a high bilirubin level mean?
It may point to liver inflammation, impaired bile flow, or increased red blood cell breakdown. The cause is usually identified by reviewing the rest of your liver panel and other test results.
Does a low bilirubin level usually cause symptoms?
Low bilirubin levels are uncommon and generally do not cause noticeable symptoms. If a result is unexpectedly low, your healthcare professional will consider your overall health and other laboratory findings.
Is this the same as a direct bilirubin test?
Not necessarily. A general bilirubin measurement may report total bilirubin, while a direct bilirubin test measures a specific form. Ask your healthcare professional which fraction was included in your results.
  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