Serum or plasma concentration of total bilirubin

Why This Test Is Done

Your healthcare provider may order a bilirubin test to diagnose or monitor conditions affecting your liver, bile ducts, or red blood cells. Common reasons include unexplained jaundice (yellowing of skin/eyes), liver disease (like hepatitis or cirrhosis), gallbladder problems, or hemolytic anemia (red blood cell destruction).

How the Test Works

A blood sample is taken from a vein in your arm. The lab separates the serum or plasma from blood cells and measures the total bilirubin concentration using a colorimetric method, often involving chemical reactions that detect bilirubin’s presence.

Sample Collection

You’ll have a small needle inserted into your arm to draw blood. This usually takes a few minutes. The site will be cleaned, and you may feel a slight pinch. If you’re nervous, let your provider know—they can use a tourniquet or apply a numbing cream if needed.

What to Expect Before the Test

No special preparation is needed, but avoid eating or drinking for 8–12 hours before the test if instructed. Wear comfortable clothing with an easy armhole. If you’re pregnant, have diabetes, or take certain medications, mention it to your provider.