Bilirubin is a yellow pigment produced in the body by the breakdown of haemoglobin. Bilirubin is processed by the liver and is then excreted into bile where it is mixed with the other constituents of bile. It then reaches the gallbladder, which secretes bile into the intestines for digestion. Bile is ultimately eliminated in the stool.
At times, the liver fails to process bilirubin due to some issues owing to which bilirubin starts to show its presence in the skin and eyes (Jaundice). Therefore, to detect the presence of bilirubin in the serum a bilirubin serum test is ordered.
Laboratory tests help in evaluating two forms of bilirubin:
- Conjugated (produced in the liver and is connected with sugars). Usually, conjugated bilirubin is not present in the blood;
- Unconjugated bilirubin (formed from haemoglobin by the elimination of haeme. Some proteins carry it to the liver). Low levels are observed in the blood.
The total bilirubin test measures both conjugated and unconjugated bilirubin.
When is the test ordered?
A doctor may prescribe a bilirubin test if a child or adult shows signs and symptoms associated with jaundice, such as dark urine, yellowing of skin, eyes, weakness, fatigue, loss of appetite, nausea, vomiting, abdominal swelling and pain.
In newborns with jaundice, the levels of bilirubin are measured and observed as a part of standard medical care. Bilirubin test may also be prescribed when an individual is suspected to be suffering from haemolytic anaemia (A condition in which red blood cells are destroyed too quickly.)
How to prepare for the test?
No special preparation is needed for this test.
How is the sample collected?
A blood sample is collected from the vein in the arm of the individual using a needle.