Newborn screening: new developments in a proven field.

1. Roger B Eaton, PhD[⇑][1] 1. is Director, New England Newborn Screening Program, University of Massachusetts Medical School, Jamaica Plain, MA 2. Anne Marie Comeau, PhD 1. is Deputy Director, New England Newborn Screening Program, University of Massachusetts Medical School, Jamaica Plain, MA 3. Thomas H Zytkovicz, PhD 1. is Chief of Labs, New England Newborn Screening Program, University of Massachusetts Medical School, Jamaica Plain, MA 4. Cecilia Larson, MD 1. is a physician at New England Newborn Screening Program, University of Massachusetts Medical School, Jamaica Plain, MA 1. Address for correspondence: Roger B Eaton PhD, Director, New England Newborn Screening Program, University of Massachusetts Medical School, 305 South Street, Jamaica Plain, MA. (617)983-6317, (617) 522-2846 (fax). roger.eaton{at}state.ma.us 1. Discuss the relationship of a test's clinical use to the assay performance measures. 2. Explain the public health issues pertaining to newborn screening. 3. Describe the newborn screening model used by the New England Newborn Screening Program (NENSP). 4. Discuss NENSP's two-tiered testing approach for cystic fibrosis. 5. Describe the use of tandem mass spectrometry in the NENSP's pilot program. 6. List the 20 tests included in NENSP's expanded pilot program. The field of newborn screening is dynamic, incorporating new technical developments that can improve the quality of life for more babies than ever before. Although ‘newborn screening’ includes screening for hearing and other disorders, in this article newborn screening will refer to public health-regulated testing of blood samples from newborns. This article on newborn screening provides opportunities to: 1) consider how the purpose of a medical test, e.g., diagnostic vs. screening, relates to assay performance measures; 2) consider newborn screening as a model for the application of laboratory science to public health; and 3) review some recent technical developments in the field. ‘SCREENING’ – RELEVANCE TO THE LABORATORIAN In designing testing algorithms and laboratory cut-offs, it is important to consider the purpose of the testing and the likely population from whom samples will be received. The primary purpose of a newborn screen test is to select from the general population of newborns (where the probability of the disorder is very low) a manageable number of babies with significantly higher risk for the targeted disorder. The purpose of a test applied to clinically presenting patients (where the prior probability for the disorder is already much greater than for the general population) is to further refine the risk for the disorder, or to establish the diagnosis. Let us consider the application of a test with a 90% sensitivity and a 99% specificity to each of the above two situations (Table 1). In the clinical diagnostic situation, the purpose of the test is… ABBREVIATIONS: CF = cystic fibrosis; IRT = immunoreactive trypsinogen; MCAD = medium chain acyl-CoA dehydrogenase deficiency; MS/MS = tandem mass spectrometry; MSUD = maple syrup urine disease; NENSP = New England Newborn Screening Program; PKU = phenylalaninemia. 1. Discuss the relationship of a test's clinical use to the assay performance measures. 2. Explain the public health issues pertaining to newborn screening. 3. Describe the newborn screening model used by the New England Newborn Screening Program (NENSP). 4. Discuss NENSP's two-tiered testing approach for cystic fibrosis. 5. Describe the use of tandem mass spectrometry in the NENSP's pilot program. 6. List the 20 tests included in NENSP's expanded pilot program. [1]: #corresp-1