Blood Test: Bilirubin



Blood Test: Bilirubin


What It Is



A bilirubin test measures the level of bilirubin (a byproduct of the
normal breakdown of old red blood cells) in the blood. Normally,
bilirubin passes through the liver and is excreted through the
intestines as bile (a yellowish colored fluid that helps in the
digestion of fats). But if that doesn't happen due to a liver disease or
other health problem, bilirubin can build up in the blood, causing the
skin to take on the yellow discoloration known as jaundice.

Bilirubin exists in two forms in the body: indirect (unconjugated)
and direct (conjugated). Indirect bilirubin, which doesn't dissolve in
water, must travel to the liver to be changed into the soluble form,
direct bilirubin.

Why It's Done



Healthy newborns — especially those who are premature — are commonly
susceptible to jaundice because their immature livers are slow to
process bilirubin. Jaundice is also fairly common among breastfeeding
babies who aren't getting enough milk, or those whose mothers naturally
produce substances that raise bilirubin levels.

Most mild cases resolve on their own. But because high bilirubin
levels can cause hearing loss and brain damage in babies, the American
Academy of Pediatrics (AAP) recommends that all infants be examined for
jaundice soon after birth. If the doctor feels that the baby is more
jaundiced than would be expected, a blood test is done to determine the
exact level of bilirubin in the blood.

Babies with high levels may need phototherapy (treatment with a
special light that makes bilirubin easier for the liver to process), or
in rare cases, a procedure called an exchange transfusion in which the
infant's bilirubin level is brought down by removing bilirubin-rich
blood from the baby and replacing it with blood that contains normal
levels of bilirubin.

High bilirubin levels in infants may also be the result of hemolytic
disease, a condition that occurs when there is an incompatibility
between the blood types of the mother and baby leading to more rapid
breakdown of the infant's red blood cells.

Doctors may order a bilirubin test in other infants or older children
who have have developed jaundice due to other conditions, such as liver
disease, bile duct blockage, or thyroid disease.

Preparation



No special preparations are needed for this test. Having your child
wear a short-sleeve shirt on the day of the test can make things faster
and easier for the technician who will be drawing the blood.The Procedure



A health professional will usually draw the blood from a vein. For an
infant, the blood may be obtained by puncturing the heel with a small
needle (lancet). If the blood is being drawn from a vein, the skin
surface is cleaned with antiseptic, and an elastic band (tourniquet) is
placed around the upper arm to apply pressure and cause the veins to
swell with blood. A needle is inserted into a vein (usually in the arm
inside of the elbow or on the back of the hand) and blood is withdrawn
and collected in a vial or syringe.

After the procedure, the elastic band is removed. Once the blood has
been collected, the needle is removed and the area is covered with
cotton or a bandage to stop the bleeding. Collecting blood for this test
will only take a few minutes.



What to Expect



Either method (heel or vein withdrawal) of collecting a sample of
blood is only temporarily uncomfortable and can feel like a quick
pinprick. Afterward, there may be some mild bruising, which should go
away in a few days.

Getting the Results



The blood sample will be processed by a machine. The results are generally available after a few hours or the next day.

Bilirubin levels are evaluated according to your child's age.

Risks



The bilirubin test is considered a safe procedure. However, as with
many medical tests, some problems can occur with having blood drawn,
such as:

• fainting or feeling lightheaded
  
• hematoma (blood accumulating under the skin causing a lump or bruise)
  
• pain associated with multiple punctures to locate a vein
  

Helping Your Child



Having a blood test is relatively painless. Still, many kids are
afraid of needles. Explaining the test in terms your child can
understand might help ease some of the fear.

Allow your child to ask the technician any questions he or she might
have. Tell your child to try to relax and stay still during the
procedure, as tensing muscles and moving can make it harder and more
painful to draw blood. It also may help if your child looks away when
the needle is being inserted into the skin.

If You Have Questions



If you have questions about the bilirubin test, speak with your doctor.