Newborn Screening Tests

What are newborn screening tests?

Newborn screening tests are tests to check for treatable diseases that can appear early in life. These tests can detect certain diseases before they cause serious damage. Newborns can then be given preventive treatment. The tests are provided by state departments of health. The diseases tested for vary somewhat from state to state.

While newborn screening tests are likely to find newborns with the diseases, like all tests, they are not perfect. Sometimes they incorrectly report a disease a child does not actually have. Therefore, all children who test positively for a disease should be tested again. Rarely, the tests do not identify children that actually do have the disease.

What diseases are tested for?

All states in the U.S. test for 4 diseases:

• hypothyroidism
• phenylketonuria (PKU)
• galactosemia
• hemoglobinopathy, including sickle-cell disease.

Hypothyroidism and phenylketonuria can cause mental retardation if they are not treated.

Many but not all states test for:

• homocystinuria
• congenital adrenal hyperplasia
• biotinidase deficiency.

If any of these rare diseases are diagnosed and treated early, they can be improved or some an even be completely cured.

Some states have recently started testing for amino acid, organic acid, and fatty acid oxidation defects. In other states these tests are only available through private testing labs. Early diagnosis and treatment of these metabolic disorders may help to prevent serious problems like mental retardation. Although these disorders cannot be cured, the serious effects may be prevented or lessened if a particular diet or medicine is started early in the child's life. Ask your health care provider about these screening tests.

How are the tests done?

The tests are run on small amounts of blood. Your child's health care provider gets the blood by making a tiny cut in the baby's heel. 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 (earlier if a screenable disease is suspected).

If a test does suggest 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 has copies of the newborn screening test results.

If your baby needs a blood transfusion, blood for the tests should be collected before the transfusion.

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

Parents may refuse to have their newborn screened because of their religious beliefs or, in many states, because of their personal beliefs. Parents who refuse to have the testing done should sign waiver forms for the medical records.

Additional information on newborn screening is available from your health care provider or from the state health department.