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Newborn Screening: Your Baby's First Blood Tests
In your baby's first days of life, a few drops of blood will be taken from his heel for the newborn screening tests, which can identify up to 40 rare medical conditions. Although these medical conditions do not usually cause symptoms in the newborn period, over time they can lead to serious health problems including poor growth, organ enlargement, seizures and mental retardation, and even death. Thankfully, most babies are found not to have these medical conditions. And for babies found to have one of these conditions, starting treatment early and maintaining it throughout the child's life will lead to much healthier growth and development.

When is the blood test done?
The blood test is typically done in the hospital before your newborn goes home. The best time is when your baby is two to three days old. To identify some of the conditions, your baby needs to have had feedings of breast milk or formula to give the body a chance to break down the nutrients.

If you and your baby are sent home from the hospital early and the test is done when your baby is less than 48 hours old, it might be too early to spot some of the medical problems. Also, if your baby was cared for the in neonatal intensive care unit (for prematurity, very low birth weight, a transfusion or antibiotic treatment), the early screening test might not be valid. In these cases, it's important to have your baby retested within the first two weeks of life. Be sure to talk with your doctor about this.

What medical conditions are covered?
Newborn screening tests check for a variety of inborn disorders of blood cells, hormone systems, metabolism (how the body breaks down nutrients from food to build tissues and make the body systems run correctly), and infectious diseases. Each of the conditions is relatively rare: up to one in 1,000 babies is found to have one of the conditions.

Every state in the United States requires its hospitals to offer newborn screening tests. However, due to variations in policies and funding, different states offer different tests; some states offer more tests and some fewer. The most common conditions tested for are:
  • Hyperphenylalanemia or phenylketonuria (PKU): This is an inherited disorder caused by a lack of an enzyme needed to break down phenylalanine, an amino acid found in many foods. Without treatment, phenylalanine builds up in the brain, damaging the nervous system and causing seizures and mental retardation. Treatment with a low-phenylalanine diet and monitoring blood levels of phenylalanine can help children grow and develop well.


  • Congenital Hypothyroidism: This condition results from the baby's inability to make enough thyroid hormone. Without treatment, babies lack energy, feed poorly, fail to grow properly and have mental retardation. Treatment with thyroid hormone can help children grow and develop well.


  • Galactosemia: This is an inherited disorder caused by the lack of an enzyme needed to break down galactose, a natural sugar in milk products. Without treatment, it leads to liver disease, seizures, mental retardation and even death. Treatment with a diet free of milk products helps children grow and develop.


  • Congenital Adrenal Hyperplasia: This disorder is caused by a lack of enzymes in the adrenal gland needed to make the hormones cortisol and aldosterone. It can lead to increased production of male sex hormones, leading to male-appearing genitalia in baby girls, growth problems, disruptions in fluid balance and even death. Treatment with the missing hormones helps children grow and remain healthy.


  • Sickle Cell Anemia: This is an inherited disorder causing sickle-shaped red blood cells. It can cause anemia, bouts of serious pain, infections and damage to organs including the lungs, kidneys and brain. Treatment with medications can help prevent some of the medical complications.
Can I get my baby tested for other medical conditions not required in my state?
Some hospitals may offer additional newborn screening tests for a fee. If your hospital does not offer them, you can get additional tests through private laboratories that typically charge from $25 to $100, depending on how many conditions they screen.

You may want to consider getting your baby tested for a larger number of conditions if your state tests for only a limited number or if you have a family history of multiple pregnancy losses, birth defects, infant deaths or developmental disabilities that may have been caused by a rare medical condition.

What if the test comes back positive?
A positive result on the screening test does not mean your baby has the condition. It means that your baby needs follow-up testing with more specific tests for the condition, which may take from weeks to months. When follow-up tests are performed, most babies who tested positive on the earlier screening test turn out not to have the condition. But if the follow-up tests indicate that your baby does have one of the medical conditions, you will need to work closely with your baby's doctor and the pediatric specialists who will prescribe and coordinate your child's treatment. This may include continual medications, special diets and laboratory tests. In addition, there are many parent advocacy organizations, educational resources and support groups that can be very helpful in caring for your child. In the case of hereditary conditions, you will also be referred to a genetic counselor to discuss recommendations for testing other family members for the condition as well as considerations for future pregnancies. In all, the treatment and support can make a tremendous difference in your child's future health and your family's well-being.

For more information, contact:

March of Dimes Birth Defects Foundation

(www.modimes.org or (888)-MODIMES) or the

National Newborn Screening and Genetics Resource Center
(http://genes-r-us.uthscsa.edu) for a list of the newborn screening tests done in your state and private laboratories that conduct additional tests.

Karen Sokal-Gutierrez M.D., M.P.H. Pediatrician