Serum or plasma concentration of bilirubin (total)

A total bilirubin test measures the amount of bilirubin, a yellowish pigment formed when old red blood cells break down, in your blood. Your doctor may order this test to check how well your liver is working, to investigate yellowing of the skin or eyes (jaundice), or to help diagnose conditions such as hepatitis, cirrhosis, bile duct blockage, or hemolytic anemia. It is also used to monitor known liver problems or the effects of certain medications.

Your doctor may order a total bilirubin test to check for conditions that affect how your liver processes bilirubin, such as jaundice (yellowing of the skin and eyes), liver disease, or gallbladder problems. It can also help identify if red blood cells are breaking down too quickly, which might indicate anemia or other blood disorders.

In most cases, no special preparation is needed for a total bilirubin test, although you may be asked to fast for several hours if it is part of a larger panel of blood tests. Before the blood draw, tell your healthcare provider about all prescription drugs, over-the-counter medicines, and supplements you take, since some can affect your results. Continue drinking water unless instructed otherwise, and plan for the blood draw itself, which takes only a few minutes.

No special preparation is needed. You may have a blood sample drawn from a vein in your arm, similar to other blood tests. If you’re on blood thinners, let your doctor know before the test.

During the test, a healthcare professional wraps an elastic band around your upper arm to make the veins easier to see, cleans the skin at the puncture site, and inserts a small needle into a vein, usually in your arm. A sample of blood is collected into a tube, the band and needle are removed, and gentle pressure with a bandage is applied to the site. Your sample is then sent to a laboratory, where the bilirubin level is measured and reported in mg/dL.

A healthcare professional will take a blood sample. The sample is sent to a lab, where bilirubin levels are measured using a chemical method that detects its presence in the serum or plasma.

For healthy adults, a typical total bilirubin result falls between about 0.1 and 1.2 mg/dL, though reference ranges can vary slightly between laboratories. Elevated levels may point to liver disease, a blocked bile duct, or faster-than-normal red blood cell breakdown, and doctors usually interpret them alongside other liver tests and your symptoms. Results below the reference range are generally not considered medically significant and rarely require follow-up.

Results are compared to a reference range, but exact values can vary by lab. High bilirubin levels may suggest liver or bile duct issues, while very low levels might raise concerns about red blood cell production.