Total Bilirubin Test
Also known as: Bilirubin, TBIL, Serum Bilirubin
What is Total Bilirubin?
Bilirubin is a yellow pigment produced when red blood cells break down. The liver processes bilirubin so it can be excreted from the body.[MedlinePlus (NIH)]
What This Test Measures
This test measures total bilirubin in the blood. It may also be broken down into direct (conjugated) and indirect (unconjugated) bilirubin.[Mayo Clinic]
Why It's Important
Bilirubin levels help diagnose liver disease, bile duct obstruction, and hemolytic anemia.[MedlinePlus (NIH)]
High bilirubin causes jaundice (yellowing of skin and eyes).[Cleveland Clinic]
Who Should Get This Test?
Bilirubin testing is important for assessing liver and blood health.
Risk Factors
- Yellowing of skin or eyes (jaundice)
- Dark urine or pale stools
- Suspected liver disease or hepatitis
- Suspected bile duct obstruction or gallstones
- Newborns (routine screening for neonatal jaundice)
- Hemolytic anemia or blood disorders
- Monitoring liver disease progression
- Gilbert syndrome evaluation
- Pre-operative assessment
- Taking medications that affect liver
Screening Schedule
Not routine for healthy adults. Ordered when jaundice or liver disease is suspected. Routine for newborns.
What Happens During the Test
A blood sample is drawn from a vein. In newborns, a heel prick or transcutaneous bilirubinometer may be used.
Duration
5 minutes for the blood draw; results usually available within 24 hours
Discomfort Level
Minimal - brief pinch from needle insertion
Risks & Side Effects
Bilirubin testing through blood draw carries very few risks.
- •Minor pain or bruising at the needle site
- •Slight bleeding
- •Rarely, lightheadedness
- •Very rare risk of infection
Normal Range
Total bilirubin: 0.1 to 1.2 mg/dL.
Note: Newborns have higher normal levels. Gilbert syndrome causes mild, harmless elevations.
Source: MedlinePlus (NIH)Unit Conversion
Convert between mg/dL and µmol/L
| mg/dL | µmol/L |
|---|---|
| 0.3 | 5.1 |
| 0.5 | 8.6 |
| 1 | 17.1 |
| 1.2 | 20.5 |
| 2 | 34.2 |
| 5 | 85.5 |
High Values
High bilirubin can indicate liver disease, bile duct obstruction, hemolytic anemia, or Gilbert syndrome. Symptoms include jaundice, dark urine, and pale stools.[Mayo Clinic]
Low Values
Low bilirubin is not typically a concern and may be seen with certain medications.[Cleveland Clinic]
Test Limitations & Accuracy
Bilirubin levels require clinical context for interpretation.
- ⚠Gilbert syndrome causes harmless elevations (affects 3-7% of population)
- ⚠Fasting can increase bilirubin levels
- ⚠Hemolysis of blood sample falsely elevates results
- ⚠Total bilirubin alone may not distinguish liver vs blood causes
- ⚠Direct/indirect fractionation needed for full picture
- ⚠Caffeine and certain medications affect levels
- ⚠Dehydration can concentrate bilirubin
Alternative & Complementary Tests
Bilirubin is interpreted alongside other liver and blood tests.
To distinguish liver disease from hemolysis
To assess liver cell damage
To assess bile duct obstruction
To evaluate for hemolytic anemia
Low haptoglobin suggests hemolysis
To visualize bile ducts and gallstones
References
Related Condition Guides
Medical Disclaimer
This information is for educational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for interpretation of test results and medical decisions.
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