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Serum/plasma mass concentration of total bilirubin

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

This test measures the total amount of bilirubin in your blood. Bilirubin is a yellow pigment produced when red blood cells break down, and it helps your liver process waste products.

Quick summary

["Your doctor may check bilirubin levels to diagnose or monitor conditions affecting your liver, bile ducts, or red blood cells."]

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

Key facts at a glance

LOINC
74634-7
Short code
DMA Pnl RBC
Synonyms
DMA Pnl RBC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
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 Is Done

Doctors order a total bilirubin test to identify or check for conditions such as jaundice (yellowing of the skin and eyes), liver disease, bile duct blockages, or hemolytic anemia (a type of red blood cell disorder). It may also be used during pregnancy to monitor fetal health or after certain surgeries.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your doctor specifies it, but this is not always required. Bring any medications or supplements you’re taking to your appointment.

How the Test Is Performed

A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight sting, but it usually lasts only a few seconds. The blood sample is then sent to a lab for analysis.

Possible Results and Interpretation

Results are reported in milligrams per deciliter (mg/dL). High levels may indicate liver or bile duct problems, while very low levels could suggest conditions like Gilbert syndrome or certain genetic disorders. Your doctor will discuss your specific results in the context of your health.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total bilirubin

Frequently asked questions

What does a high bilirubin level mean?
A high bilirubin level often signals an issue with your liver, bile ducts, or red blood cells. For example, liver diseases like hepatitis or cirrhosis, blockages in the bile ducts, or hemolytic anemia can cause elevated bilirubin. Early detection helps manage these conditions more effectively.
What does a low bilirubin level mean?
Low bilirubin levels are less common and may occur with certain genetic conditions (like Gilbert syndrome) or in people with severe liver disease who have lost most of their liver function. Your doctor will consider your overall health and symptoms to interpret results.
Can bilirubin levels change over time?
Yes, bilirubin levels can fluctuate due to changes in liver function, blood cell turnover, or underlying medical conditions. Regular monitoring may be needed if you have a history of liver disease, bile duct issues, or other conditions affecting bilirubin metabolism.
  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