The bilirubin test is a common and essential procedure for newborns. It measures the level of bilirubin in the baby’s blood. Bilirubin is a yellow substance produced during the normal breakdown of red blood cells. Normally, bilirubin passes through the liver, which converts it into a form that can be eliminated from the body through stool. However, in newborns, especially those born prematurely, the liver may not be mature enough to process bilirubin efficiently, leading to a condition called jaundice.
Why is a Bilirubin Test Important for Infants?
The bilirubin test is critical because high levels of bilirubin in an infant’s blood can lead to jaundice, a condition that causes the skin and whites of the eyes to turn yellow. While jaundice is common in newborns and often harmless, if the bilirubin levels become too high, it can cause a more severe condition known as kernicterus. Kernicterus can lead to brain damage, hearing loss, and other serious complications. The bilirubin test helps healthcare providers monitor bilirubin levels to ensure they remain within a safe range and provide treatment if necessary.
Understanding Bilirubin and Its Role in the Body
Bilirubin is a byproduct of the normal breakdown of hemoglobin, a protein in red blood cells that carries oxygen. When red blood cells break down, hemoglobin is released and converted into bilirubin. The liver then processes bilirubin, making it water-soluble so it can be excreted in bile and eliminated from the body through feces.
In infants, the process of bilirubin breakdown and elimination is not fully developed at birth. This is especially true for premature babies whose liver function may not be fully mature. As a result, bilirubin can build up in the blood, leading to jaundice. While mild jaundice is common and usually resolves on its own, high levels of bilirubin can be dangerous.
Types of Bilirubin
There are two types of bilirubin that can be measured in a bilirubin test: direct (conjugated) bilirubin and indirect (unconjugated) bilirubin.
Indirect Bilirubin:
This is the form of bilirubin produced immediately after the breakdown of red blood cells. It is not yet processed by the liver, so it is not water-soluble and cannot be eliminated from the body. This form of bilirubin is usually responsible for jaundice in newborns.
Direct Bilirubin:
After indirect bilirubin is processed by the liver, it becomes direct bilirubin. This form is water-soluble and can be excreted from the body. High levels of direct bilirubin may indicate a problem with the liver or bile ducts.
Why Do Newborns Need a Bilirubin Test?
Most newborns are tested for bilirubin levels as part of their routine care. The test is usually done within the first 24 to 48 hours after birth. Some factors increase the risk of high bilirubin levels in newborns, making the test particularly important in these cases:
Premature Birth:
Babies born before 37 weeks of gestation are at higher risk because their livers are less mature and less able to process bilirubin effectively.
Blood Type Incompatibility:
If the mother and baby have different blood types, the baby’s red blood cells may break down more quickly, leading to higher bilirubin levels.
Family History of Jaundice:
A family history of jaundice or liver problems can increase the risk of high bilirubin levels.
Bruising During Birth:
If the baby experiences bruising during birth, the breakdown of red blood cells in the bruised areas can lead to higher bilirubin levels.
How is the Bilirubin Test Performed?
The bilirubin test is a simple blood test. There are two main ways to measure bilirubin levels in infants:
Transcutaneous Bilirubin Measurement (TcB):
This is a non-invasive method that uses a special device placed on the baby’s skin to measure bilirubin levels. The device emits a light that reflects off the bilirubin in the baby’s skin, providing an estimate of the bilirubin level.
Blood Bilirubin Test:
A small sample of the baby’s blood is taken, usually from the heel, and sent to a lab for analysis. This method provides a more accurate measurement of bilirubin levels than the transcutaneous method.
Interpreting Bilirubin Test Results
Bilirubin levels are measured in milligrams per deciliter (mg/dL). The normal range for bilirubin in a newborn is typically between 0.2 to 1.2 mg/dL. However, levels can vary depending on the baby’s age in hours, gestational age, and overall health.
Normal Levels:
Bilirubin levels below 5 mg/dL are generally considered normal and not likely to cause jaundice.
Moderate Levels:
Levels between 5 and 15 mg/dL may cause mild to moderate jaundice but are usually not harmful.
High Levels:
Levels above 15 mg/dL require close monitoring and possibly treatment to prevent complications such as kernicterus.
What Happens if Bilirubin Levels are High?
If a newborn’s bilirubin levels are high, the healthcare provider may recommend treatment to lower the levels and prevent complications. The type of treatment depends on how high the bilirubin levels are and how quickly they are rising.
SEE ALSO: What Are the Effects of High Bilirubin in Newborns?
Phototherapy:
This is the most common treatment for high bilirubin levels in newborns. The baby is placed under a special light that helps break down bilirubin in the skin, making it easier for the body to eliminate. Phototherapy can be done in the hospital or at home, depending on the severity of the jaundice.
Exchange Transfusion:
In severe cases of jaundice, where bilirubin levels are extremely high or not responding to phototherapy, an exchange transfusion may be necessary. This procedure involves slowly removing the baby’s blood and replacing it with fresh donor blood. This helps reduce bilirubin levels quickly.
Intravenous Immunoglobulin (IVIg):
If jaundice is caused by blood type incompatibility, IVIg may be given to reduce the level of antibodies in the baby’s blood that are attacking the red blood cells.
Monitoring and Follow-Up
After treatment, the baby’s bilirubin levels will be closely monitored to ensure they are decreasing. In some cases, the baby may need to stay in the hospital for observation until bilirubin levels return to a safe range. Follow-up appointments are also important to check the baby’s progress and ensure that jaundice does not recur.
Preventing High Bilirubin Levels
While it is not always possible to prevent high bilirubin levels, there are some steps that parents and healthcare providers can take to reduce the risk:
Breastfeeding:
Frequent breastfeeding helps the baby pass bilirubin through stool, which can help lower bilirubin levels. Newborns should be breastfed at least 8 to 12 times a day in the first few days of life.
Monitoring:
Babies at risk for high bilirubin levels, such as those born prematurely or with a family history of jaundice, should be monitored closely for signs of jaundice.
Early Detection:
Early detection of jaundice through regular check-ups and bilirubin testing can help prevent complications.
Conclusion
The bilirubin test is a crucial part of newborn care, helping to detect and manage jaundice before it leads to serious complications. By understanding the importance of the bilirubin test, parents can ensure their newborn receives the best possible care and support during the first days of life. Regular monitoring, prompt treatment, and proper breastfeeding practices can help keep bilirubin levels within a safe range, ensuring a healthy start for the baby.
