A bilirubin test measures the amount of bilirubin in a blood sample. The results are usually available in 1 to 2 hours.
Normal values in adults
The normal values listed here-called a reference range-are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Bilirubin levels in adults
| Bilirubin type
0.0-1.4 mg/dL or 1.7-20.5 mcmol/L
0.0-0.3 mg/dL or 1.7-5.1 mcmol/L
0.2-1.2 mg/dL or 3.4-20.5 mcmol/L
- High levels of bilirubin in the blood may be caused by:
- Some infections, such as an infected gallbladder, or cholecystitis.
- Some inherited diseases, such as Gilbert's syndrome, a condition that affects how the liver processes bilirubin. Although jaundice may occur in some people with Gilbert's syndrome, the condition is not harmful.
- Diseases that cause liver damage, such as hepatitis, cirrhosis, or mononucleosis.
- Diseases that cause blockage of the bile ducts, such as gallstones or cancer of the pancreas.
- Rapid destruction of red blood cells in the blood, such as from sickle cell disease or an allergic reaction to blood received during a transfusion (called a transfusion reaction).
- Medicines that may increase bilirubin levels. This includes many antibiotics, some types of birth control pills, diazepam (Valium), flurazepam, indomethacin (Indocin), and phenytoin (Dilantin).
Low levels of bilirubin in the blood may be caused by:
Normal values in newborns
Normal values in newborns depend on the age of the baby in hours and whether the baby was premature or full term. Normal values may vary from lab to lab.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful (except in newborns) include:
Caffeine, which can lower bilirubin levels.
- Not eating for a long period (fasting), which normally increases indirect bilirubin levels.