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Serum or plasma concentration of total bilirubin (indirect fraction)

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

This test measures the indirect (unconjugated) form of bilirubin, a yellow pigment produced when red blood cells break down. It helps assess liver function and the body’s ability to process bilirubin properly.

Quick summary

["Indirect bilirubin helps diagnose conditions affecting bilirubin metabolism, such as hemolysis or liver disease."]

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

Key facts at a glance

LOINC
41123-1
Short code
T gondii HS Ab Ser-aCnc
Synonyms
T gondii HS Ab Ser-aCnc
Category
chemistry
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

Why This Test Matters

Your liver normally processes bilirubin by attaching it to proteins before it’s excreted in bile. If the indirect bilirubin level rises, it may indicate problems like red blood cell breakdown (hemolysis), liver disease, or bile duct blockage that prevent bilirubin from being processed efficiently.

What to Expect Before the Test

No special preparation is needed. You may fast for 8–12 hours before the test if instructed, but this is not always required. Bring your lab slip and wear comfortable clothing for blood draws.

How the Test Works

A blood sample is taken from a vein, usually in your arm. The lab separates the serum or plasma and measures the indirect bilirubin concentration using a specialized chemical method.

Possible Causes of Abnormal Results

High indirect bilirubin can result from conditions like Gilbert’s syndrome (mild genetic liver issue), hemolytic anemia (destruction of red blood cells), or liver inflammation (hepatitis). Low levels are less common but may occur with severe liver disease or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Indirect bilirubin

Frequently asked questions

What does a high indirect bilirubin mean?
A high indirect bilirubin suggests your body isn’t processing bilirubin correctly, which may signal hemolysis (rapid red blood cell breakdown) or liver dysfunction. Your doctor will review your full lab profile and symptoms to determine the cause.
What if my indirect bilirubin is normal?
A normal result doesn’t rule out all causes of bilirubin issues, but it indicates your liver and red blood cells are functioning within typical ranges for this test. Follow-up may still be needed if you have symptoms like jaundice or fatigue.
How often should I get this test?
Your doctor will schedule this test based on your symptoms, medical history, or routine health checks. For example, it may be part of a liver function panel or if you have conditions like hemolytic anemia or hepatitis.
  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