Newborn screening tests look for developmental, genetic, and metabolic disorders in the newborn baby. This allows steps to be taken before symptoms develop. Most of these illnesses are very rare, but can be treated if caught early.

The types of newborn screening tests that are done vary from state to state. By April 2011, all states reported screening for at least 26 disorders on an expanded and standardized uniform panel. The most thorough screening panel checks for about 40 disorders. However, because phenylketonuria (PKU) was the first disorder for which a screening test developed, some people still call the newborn screen "the PKU test".

In addition to blood tests, screening for hearing loss and critical congenital heart disease (CCHD) is recommended for all newborns. Many states require this screening by law as well.

How the Test is Performed

Screenings are done using the following methods:

• Blood tests. A few drops of blood are taken from the baby's heel. The blood is sent to a lab for analysis.
• Hearing test. A health care provider will place a tiny earpiece or microphone in the infant's ear. Another method uses electrodes that are put on the baby's head while the baby is quiet or asleep.

  Hearing test

  Hearing loss is not being able to hear sound in one or both ears. Infants may lose all of their hearing or just part of it.

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• CCHD screen. A provider will place a small soft sensor on the baby's skin and attach it to a machine called an oximeter for a few minutes. The oximeter will measure the baby's oxygen levels in the hand and foot.

How to Prepare for the Test

There is no preparation needed for newborn screening tests. The tests are most often done before leaving the hospital when the baby is between 24 hours and 7 days old.

How the Test will Feel

The baby will most likely cry when the heel is pricked to get the blood sample. Studies have shown that babies whose mothers hold them skin-to-skin or breastfeed them during the procedure show less distress. Wrapping the baby tightly in a blanket, or offering a pacifier dipped in sugar water, may also help ease pain and calm the baby.

The hearing test and the CCHD screen should not cause the baby to feel pain, cry, or respond.

Why the Test is Performed

Screening tests do not diagnose illnesses. They show which babies need more testing to confirm or rule out illnesses.

If follow-up testing confirms that the child has a disease, treatment can be started, before symptoms appear.

Blood screening tests are used to detect a number of disorders. Some of these may include:

• Amino acid metabolism disorders
• Biotinidase deficiency
• Congenital adrenal hyperplasia

  Congenital adrenal hyperplasia

  Congenital adrenal hyperplasia is the name given to a group of inherited disorders of the adrenal gland. Inherited means the traits are passed down ...

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• Congenital hypothyroidism

  Hypothyroidism

  Neonatal hypothyroidism is decreased thyroid hormone production in a newborn. In very rare cases, no thyroid hormone is produced.  The condition is ...

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• Cystic fibrosis

  Cystic fibrosis

  Cystic fibrosis is a disease that causes thick, sticky mucus to build up in the lungs, digestive tract, and other areas of the body. It is one of th...

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• Fatty acid metabolism disorders
• Galactosemia

  Galactosemia

  Galactosemia is a condition in which the body is unable to use (metabolize) the simple sugar galactose.

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• Glucose-6-phosphate dehydrogenase deficiency (G6PD)
• Human immunodeficiency disease (HIV)
• Organic acid metabolism disorders
• Phenylketonuria (PKU)

  Phenylketonuria

  Phenylketonuria (PKU) is a rare condition in which a baby is born without the ability to properly break down an amino acid called phenylalanine....

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• Sickle cell disease and other hemoglobin disorders and traits

  Sickle cell disease

  Sickle cell disease is a disorder passed down through families. The red blood cells that are normally shaped like a disk take on a sickle or crescen...

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• Toxoplasmosis

  Toxoplasmosis

  Congenital toxoplasmosis is a group of symptoms that occur when an unborn baby (fetus) is infected with the parasite Toxoplasma gondii.

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• Severe combined immunodeficiency (SCID)

Normal Results

Normal values for each screening test may vary depending on how the test is performed.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

An abnormal result means that the child should have additional testing to confirm or rule out the condition.

Risks

Risks for the newborn heel prick blood sample include:

• Pain
• Possible bruising at the site where the blood was obtained

Considerations

Newborn testing is critical for the baby to receive early treatment. Treatment may be lifesaving. However, not all disorders that can be detected can be treated.

Although hospitals do not perform all screening tests, parents can have other tests done at large medical centers. Private labs also offer newborn screening. Parents can find out about extra newborn screening tests from their provider or the hospital where the baby is born. Groups like the March of Dimes -- www.marchofdimes.org also offer screening test resources.

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