Bilirubin test - Bilirubin Blood Test, Reasons, Preparation, Procedure, Definition

Bilirubin Definition

Bilirubin is found in the bile. It is a brownish yellow substance produced by the liver and is used to break down old red blood cells. Bilirubin is excreted from the body through stools, giving it its brown color.

Bilirubin is found in two forms:

• Unconjugated or indirect bilirubin which is insoluble and is carried by the blood to the liver, where it is changed to a soluble form.
• Conjugated or direct bilirubin which is soluble.

When bilirubin levels are high, the whites of the eyes and skin appear yellow (jaundice). This could be caused by liver disease, blood disorders or blockage of the bile ducts.

In newborn babies too much bilirubin can have serious effects such as brain damage, hearing loss or even death.

Reasons for Bilirubin test

• Check for liver diseases such as hepatitis or cirrhosis.
• Bilirubin test for newborns finds out the cause of jaundice and decides the form of treatment.

Procedure to conduct Bilirubin test

• In adults blood is usually drawn from a vein or artery in the arm, while for newborns, it is taken from the heel.
• Adults are advised not to eat or drink anything for 4 hours prior to a test. Newborns need no special preparation.
• The health professional cleans the vein or artery from where the blood will be drawn and punctures it with a needle.
• In newborns, a few drops of blood are collected from the heel. However, a new device – transcutaneous bilirubin meter – does away with the need to puncture the skin. When placed against the baby’s skin, it reads out the bilirubin count.

Preparation for Bilirubin test

Preparation

Inform your doctor in case you are allergic to certain medicines or are taking certain medicines, especially blood thinners such as warfarin or aspirin, or if you are pregnant.

Results for Bilirubin test

The bilrubin test measures the quantities of bilirubin present in a sample of blood. The results are available in a couple of hours. The results are checked against a bilirubin chart, which displays the range deciding whether the levels vary from normal to abnormal.

Some factors that affect the test

Sometimes, the results of a test may not be conclusive because of certain factors:

• Intake of caffeine just before the test lowers bilirubin levels.
• Fasting or not eating for a prolonged period before the test increases the levels of indirect bilirubin.

Some other tests for bilirubin

Sometimes, the amniotic fluid is tested for levels of bilirubin, in case doctors suspect that the unborn baby may have erythroblastosis fetalis, which destroys red blood cells.
Sometimes, bilirubin is measured in the urine. Since urine should not contain it, its presence indicates that the liver is not functioning properly.