Newborn Screening Tests

What are newborn screening tests?

Newborn screening tests are tests given to infants within a few days after birth. These tests check for disorders that could cause serious harm and can only be found by blood tests. The tests are provided by your state’s department of health. Different states have different rules about which tests are done.

Newborn screening tests are accurate but they are not perfect. Sometimes they show that a child has a disease that the child does not actually have. This is particularly a concern when the true disease is very, very rare. Therefore all children who test positively for a disease should be tested again. Rarely, the tests do not identify children who actually do have a disease.

What diseases are tested for?

All states in the U.S. test for diseases in these categories:

• Hemoglobin disorders. Tests can detect sickle cell anemia, hemoglobin C, and other blood disorders. A severe shortage of normal red blood cells may cause weakness, shortness of breath, or even heart failure.
• Endocrine disorders. Disorders such as congenital adrenal hyperplasia and hypothyroidism can be detected. Both of these disorders can seriously affect a baby and both are able to be well treated with medicines.
• Cystic fibrosis. This disease affects the lungs and other organs and is helped by early treatment.
• Galactosemia. This condition can cause blindness, mental retardation, and growth problems if not treated.
• Biotinidase deficiency. This condition may lead to seizures, hearing loss, mental retardation, and problems with the immune system.
• Phenylketonuria (PKU). This can cause mental retardation if not treated early.
• Most states also screen for a variety of fatty acid, organic acid and amino acid disorders. Some examples of conditions screened for in all states are:
  • Homocystinuria. This causes mental retardation, blood clotting problems, and skeletal problems.
  • Maple syrup urine disease. Without treatment, this can cause severe mental retardation.
  • Glutaric academia. This condition varies widely in severity and may be helped by a diet that includes medical foods and formulas.

If these rare diseases are diagnosed early, some of them can be effectively treated. Some can be completely cured. Unfortunately some children will not improve very much from early diagnosis.

Hearing tests are also part of newborn screening in 35 states. The newborn needs to be quiet or asleep for this test. The test measures brain waves that result when a sound is made. Reduced hearing is a frequently occurring birth defect. If hearing loss is not treated early, speech, language and learning can be affected.

How are the tests done?

Your child's healthcare provider makes a tiny cut in the baby's heel to get a small amount of blood to test. Well infants are usually tested just before they go home from the hospital, but not later than 72 hours after birth. Sick or premature infants are tested at 1 week of age, or earlier if a disease is suspected.

If a test suggests your child has a disease, the health department will contact you and your baby's doctor. If the tests do not show any diseases, you will generally not be contacted. Your baby's doctor usually gets copies of the newborn screening test results.

Some states provide a second set of newborn screening tests between 1 and 2 weeks of age. This is important if the newborn leaves the hospital less than 24 hours after birth.

Parents may refuse to have their newborn screened because of religious or personal beliefs. Parents who refuse to have the testing done must sign forms stating they refuse the tests.

You can get more information on newborn screening from your healthcare provider or from the state health department.