Newborn screening tests
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. Most states require three to eight tests. Some organizations such as the March of Dimes and the American College of Medical Genetics suggest more than two dozen additional tests.
The most thorough screening panel checks for about 40 disorders. All 50 states screen for congenital hypothyroidism, galactosemia, and phenylketonuria (PKU).
In addition to the newborn screening blood test, a hearing screen is recommended for all newborns.
Infant screening tests; Neonatal screening tests; The PKU test
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.
How to Prepare for the Test
There is no preparation needed for newborn screening tests. The tests are done when the baby is between 24 hours and 7 days old. Most of the time, screens are done before the baby goes home from the hospital.
How the Test Will Feel
The baby will most likely cry when his or her 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 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.
Screening tests are used to detect a number of disorders. Some of these include:
- Amino acid metabolism disorders
- Biotinidase deficiency
- Congenital adrenal hyperplasia
- Congenital hypothyroidism
- Cystic fibrosis
- Fatty acid metabolism disorders
- Glucose-6-phosphate dehydrogenase deficiency (G6PD)
- Human immunodeficiency disease (HIV)
- Organic acid metabolism disorders
- Sickle cell disease and other hemoglobinopathy disorders and traits
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 doctor 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.
What the Risks Are
Risks for the newborn heel prick blood sample include pain and possible bruising at the site where the blood was obtained.
Newborn testing is critical for the baby to receive treatment. Treatment may be lifesaving. However, not all disorders that can be detected can be treated.
Although states 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 doctor or the hospital where the baby is born. Groups like the March of Dimes also offer screening test resources.
Sahai I, Levy HL. Newborn screening. In: Gleason, ed. Avery’s Diseases of the Newborn. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 27.
Lo SF. Laboratory testing in infants and children. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 707.
American College of Medical Genetics Newborn Screening Expert Group. Newborn screening: toward a uniform screening panel and system--executive summary. Pediatrics. 2006 May;117(5 Pt 2):S296-307.
Morrow C et al. Reducing Neonatal Pain during Routine Heel Lance Procedures. MCN, The American Journal of Maternal/Child Nursing, November/December 2010; (35)6:346 – 354.
Smith L. Updated AAP Guidelines on Newborn Screening and Therapy for Congenital Hypothyroidism. Am Fam Physician. 2007; 76(3).
Levy PA. An overview of newborn screening. J Dev Behav Pediatr. 2010 Sep;31(7):622-31.