Serum or plasma concentration of free bilirubin
This test measures the amount of bilirubin that is not bound to proteins in your blood. Bilirubin is a yellow pigment produced when red blood cells break down.
["Free bilirubin helps diagnose liver or bile duct issues and monitor conditions like jaundice."]
Key facts at a glance
- LOINC
- 28067-7
- Short code
- Hgb F Amn Ql
- Synonyms
- Hgb F Amn Ql
- Category
- hematology
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Ref low
- 12
- Ref high
- 17.5
- Critical range
- 7 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85018
- SNOMED
- 900000000000003004
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
Your doctor may order this test to check for liver disease, bile duct blockages, or other conditions that affect how your body processes bilirubin. High levels can indicate problems like hepatitis, gallstones, or certain blood disorders.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into a vein in your arm to draw blood. If you’re fasting, follow your doctor’s instructions about when to eat or drink.
What the Results Mean
Results are compared to a standard range, but exact values depend on your health and lab. High levels may signal liver or bile duct problems, while low levels could be normal or due to certain medications.
Common Conditions Monitored
This test is often used to diagnose or monitor conditions like jaundice (yellowing of skin/eyes), liver disease, or hemolytic anemia (red blood cell breakdown). It can also help track treatment progress.
Reference range
Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated free bilirubin can signal liver dysfunction, bile duct obstructions, or red blood cell disorders. Doctors may also check it after certain surgeries or treatments to ensure your body is processing bilirubin correctly. Low levels alone usually aren’t concerning unless paired with other symptoms or medical history.
Short name
Free bilirubin
Frequently asked questions
How is this test different from total bilirubin?
What causes free bilirubin to rise?
Can diet affect free bilirubin test results?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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