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Serum or plasma total bilirubin (concentration)

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

This test measures the total amount of bilirubin in your blood, a yellow pigment produced when red blood cells break down. It helps assess liver function and bile flow.

Quick summary

["Your liver processes bilirubin, and high levels may signal liver or bile duct issues."]

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

Key facts at a glance

LOINC
35975-2
Short code
MR LE-Bl
Synonyms
MR LE-Bl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
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

Bilirubin is normally processed by your liver and excreted through bile into your intestines. If your liver isn’t working well, bilirubin can build up in your blood, leading to jaundice (yellowing of skin/eyes). This test helps doctors check for liver diseases, bile blockages, or other conditions affecting bilirubin metabolism.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample (serum or plasma) or, rarely, urine. Avoid alcohol or certain medications (like some painkillers) for 24 hours before testing if instructed by your provider.

Common Causes of Abnormal Results

High bilirubin levels may indicate liver diseases (e.g., hepatitis), bile duct obstructions, hemolytic anemia (rapid red blood cell breakdown), or Gilbert’s syndrome (a mild genetic condition). Low levels are less common but may occur with severe liver damage or certain medications.

What the Results Mean

Results are compared to standard ranges for your age/health. Elevated levels often prompt further testing (e.g., liver function tests, imaging) to diagnose the underlying cause.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total bilirubin

Frequently asked questions

Could I get jaundice from this test alone?
No, jaundice appears when bilirubin builds up in your body, not from the test itself. High results suggest a need for additional evaluation.
Does diet affect bilirubin levels?
Dietary factors like fiber or vitamin K may indirectly influence liver function, but they don’t directly alter bilirubin. Follow your doctor’s advice if you have liver-related symptoms.
When should I ask for this test?
Ask for this test if you have symptoms like jaundice (yellow skin), dark urine, fatigue, or if your doctor suspects liver/bile issues during a routine checkup.
  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