Alternate Names : Direct Bilirubin, Indirect Bilirubin, Conjugated Bilirubin, Total Bilirubin, Unconjugated Bilirubin
A bilirubin test measures the amount of bilirubin in the blood.
Hemoglobin is the protein that binds oxygen in red blood cells. When hemoglobin
breaks down, it produces bilirubin. The liver processes bilirubin. If liver cells are
damaged, bilirubin can escape into the bloodstream. Indirect or unconjugated
bilirubin tests measure the bilirubin that has just been made by the breakdown
of hemoglobin in the body. Once bilirubin has been processed in the liver, it
can be measured as direct or conjugated. Sometimes the total amount
of bilirubin in the blood is measured.
Who is a candidate for the test?
The bilirubin test is often done when a doctor suspects liver or
The person may have jaundice,
which causes yellowed eyes and skin. A buildup of bilirubin causes jaundice.
How is the test performed?
To measure bilirubin levels, a lab technician takes a blood sample
from a vein in the forearm or hand. First, he or she cleans the skin over the vein
with an antiseptic. Next, a rubber tube called a tourniquet is wrapped
around the upper arm. This restricts blood flow in the veins in the lower arm.
And that causes them to enlarge. A fine needle is gently inserted into the
enlarged vein, and the tourniquet is removed. Blood flows from the vein through
the needle into a vial. After the needle is withdrawn, the technician covers
the puncture site with a bandage.