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Serum or plasma concentration of total bilirubin

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of bilirubin, a yellow pigment produced when red blood cells break down. It helps assess liver function and detect conditions like jaundice or bile duct blockages.

Quick summary

["Bilirubin levels can signal liver or bile flow issues."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
103131-9
Short code
S aureus Etx E IgE RAST
Synonyms
S aureus Etx E IgE RAST
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302774002
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 Is This Test Done?

Your doctor may order a bilirubin test to check for liver diseases, such as hepatitis, cirrhosis, or bile duct problems. It can also help diagnose conditions like hemolytic anemia (where red blood cells break down too quickly) or gallstones. Sometimes, it’s used to monitor treatment progress or check for complications in newborns, like jaundice.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood draw (serum or plasma) or, in some cases, a urine sample collected over 24 hours. If you’re taking certain medications, let your doctor know, as they might affect results.

What the Results Mean

High bilirubin levels may indicate liver disease, bile duct blockage, or red blood cell disorders. Low levels are less common but could signal liver disease or certain genetic conditions. Your doctor will interpret results in the context of your symptoms and overall health.

Common Conditions Linked to Bilirubin Levels

Elevated bilirubin is often seen in jaundice (yellowing of skin/eyes), liver infections (hepatitis), liver scarring (cirrhosis), or blockages in the bile ducts. Low levels may rarely suggest liver dysfunction or metabolic issues.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total bilirubin

Frequently asked questions

How often should I get this test?
Your doctor will determine how often you need this test based on your medical history, symptoms, and treatment plan. For example, newborns may get frequent checks for jaundice, while adults might have it periodically if they have liver-related conditions.
Can diet or supplements affect bilirubin levels?
Some foods or supplements (like vitamin K or certain herbs) may indirectly influence liver function, which could affect bilirubin. Always discuss your diet, supplements, or medications with your doctor before testing.
Is there anything I should avoid before the test?
No specific restrictions apply, but avoid alcohol or heavy meals 24 hours before blood testing, as they may temporarily alter liver function and 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 17, 2026. · Read our editorial policy