Serum or plasma concentration of total bilirubin

This test measures the amount of bilirubin, a yellow pigment formed when red blood cells break down, in your blood. It helps your doctor check how well your liver is working and find the cause of symptoms such as yellowing of the skin or eyes, dark urine, or unusual tiredness.

Your doctor may order this test to check for liver problems, such as hepatitis, bile duct blockages, or other conditions affecting how your liver processes bilirubin. It can also help diagnose jaundice (yellowing of the skin and eyes) or monitor conditions like hemolytic anemia (where red blood cells break down too quickly).

Your doctor may ask you not to eat or drink for several hours before the test, especially if other blood tests are being done at the same time. Tell your care team about all medicines, vitamins, and supplements you take, because some of them can affect your results.

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

A nurse or technician will wrap a band around your upper arm, clean the site, and draw a small sample of blood from a vein, usually in your arm. You may feel a quick pinch or sting. The sample is then sent to a laboratory, and the entire process usually takes just a few minutes.

A healthcare provider will clean the area with an antiseptic, insert a small needle into your vein, and collect a blood sample. The process usually takes a few minutes. You may feel a brief pinch, but it’s generally quick and painless.

Bilirubin levels that are higher than normal may point to liver conditions such as hepatitis or cirrhosis, a blocked bile duct, or a faster-than-normal breakdown of red blood cells, such as hemolytic anemia. Low levels are usually not a concern. Your doctor will review your results with you and explain what they mean for your health.

High bilirubin levels may indicate liver disease, bile duct problems, or red blood cell disorders. Low levels are less common but could suggest certain liver or bile issues. Your doctor will interpret results in the context of your overall health and symptoms.