Newborn Screening TestsDefinition: Newborn screening tests look for serious�developmental and genetic disorders�so that important action can be taken during the critical time before symptoms develop. In the U.S., the individual states each regulate newborn screening, so the diseases screened vary considerably. Most states�require�three to eight tests, but�organizations such as the March of Dimes suggest more than two dozen additional tests.�The most thorough screening panel checks for about 40 disorders. All 50 states screen�for congenital hypothyroidism.
Alternative Names: Infant screening tests
How the test is performed: Blood tests: A�health care professional will prick the babys heel to obtain a drop or two of blood. The blood is sent to a lab for analysis. Hearing test: An audiologist will place a tiny earpiece or microphone in the infants ear or stick electrodes on the babys head.
How to prepare for the test: There is no preparation necessary for newborn screening tests. The tests are performed when the baby is between 24 hours and�7 days old, typically 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 priced to obtain the small blood sample. 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 identify which babies need additional testing to confirm or rule out illnesses. Good screening tests have a low false-negative rate (if the test is normal, the child should be healthy), but may have a high false-positive rate (as many affected children as possible should test positive, even if this means many healthy children also test positive). If a disorder is diagnosed on follow-up testing, appropriate treatment can be started right away, before symptoms appear. Screening tests are used to detect a number of disorders, including: Specific Tests: - Acylcarnitine profile. This test�screens for organic acid and fatty acids disorders, including methylmalonic acidemia (MMA).
- Amino acid profile. This test�looks for amino acid deficiencies such as maple syrup urine disease� and�phenylketonuria�.�����
- APGAR. The APGAR test is performed�one to five�minutes after birth. Observers�evaluate heart rate, breathing, activity,�and skin color to detect which babies may need extra medical attention in the delivery room.
Normal Values: Normal values for each screening test� may vary depending on how the test is performed.
What abnormal results mean: An abnormal result does not mean that the baby has the indicated illness. Overall, most babies who have an abnormal screening result turn out not to have the illness. However, an abnormal result does mean 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.
Special considerations: Newborn testing is critical for the baby to receive treatment that may be life saving. However, not all disorders that can be detected by the screening tests can be treated. Although�states do not perform all�screening tests, parents can have� additional tests done by qualified laboratories at large medical centers. Private laboratories also offer newborn screening. Parents can find out about extra newborn screening tests from their physician or hospital where the baby will be born, as well as through organizations like the March of Dimes.
References: Graves JC, Miller KE, Sellers AD. Maternal serum triple analyte screening in pregnancy. Am Fam Physician. 2002 Mar 1;65(5):915-20. Grosse SD, Boyle CA, Cordero JF. Newborn screening for cystic fibrosis: recommendations from the Centers for Disease Control and Prevention. Am Fam Physician. 2005 Apr 15;71(8):1482, 1487. Bryant KG, Horns KM, Longo N, Schiefelbein J. A primer on newborn screening. Adv Neonatal Care. 2004 Oct;4(5):306-17. Carreiro-Lewandowski E. Newborn screening: an overview. Clin Lab Sci. 2002 Fall;15(4):229-38. Centers for Disease Control and Prevention. Newborn Screening for Cystic Fibrosis: Evaluation of Benefits and Risks and Recommendations for State Newborn Screening Programs. J Pediatr. 2005 Sep;147(3 Suppl):S1. Grosse SD, Boyle CA, Botkin JR, et al. Newborn screening for cystic fibrosis: evaluation of benefits and risks and recommendations for state newborn screening programs. MMWR Recomm Rep. 2004 Oct 15;53(RR-13):1-36.
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