These tests should be considered screening tests only. Screening can indicate the possibility that an infant may be at risk for a disorder included in the testing panel. Additional diagnostic tests are necessary to determine if the infant with an abnormal screening test actually has a disorder.
Not all affected infants may be identified through screening. The accuracy of screening tests depends on various factors, including the way the specimen is collected, infant’s age at testing, birth weight, gestational age, feeding type, transfusion status, medications and the presence of co-existing illness or medical conditions. If any infant with normal screening test results has symptoms of a disorder or medical problems associated with metabolic disorders, further diagnostic tests may be necessary regardless of the baby’s newborn screening results. While newborn screening has been proved reliable in the early detection of some metabolic and endocrine disorders, as with any laboratory tests, false positive and false negative results are possible. For this reason, it is critical for health care providers to remain watchful for any sign or symptoms of these disorders in their patients.
The Screening Program has numerous quality assurance, educational and monitoring mechanisms in place to assure that all infants are screened and that the results are valid. However, the possibility of a disorder should never be ruled out solely on the basis of the screening results. Any signs or symptoms of a disorder should be followed up immediately.