I want to thank Green et al. for discussing important challenges and complexities in newborn screening (NBS).1 However, in their review of NBS for cystic fibrosis, Green et al. only considered programs that applied an immunoreactive tryspsinogen (IRT) screen that “triggered genetic analysis”1(p1957) for those with a positive screen. As Green et al. realize, although most US programs use an IRT/DNA methodology, not all do so.2 Rather, some use an IRT/IRT method, although this method has the disadvantage of requiring a second blood sample.2 However, there has been some work on using a pancreatitis-associated protein enzyme-linked immunosorbent assay combined with the IRT,3 and this can be done on a single sample with approximately 100% sensitivity and a false-positive rate less than 0.25%.3
Why should we consider a non–genetic-based alternative? As Green et al. note, “the detection rate of DNA mutation testing is highly dependent on racial and ethnic background.”1(p1958) The panels in use in the United States are much less sensitive for African American and Hispanic children, and therefore, the decision to use IRT/DNA may contribute to health care disparities.
Given its public health focus on identifying all children with treatable diseases, testing methodologies for NBS should be chosen to improve, not worsen, current health care disparities.
References
- 1.Green NS, Dolan SM, Murray TH. Newborn screening: complexities in universal genetic testing. Am J Public Health. 2006;96:1955–1959. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Wilfond BS, Gollust SE. Policy issues for expanding newborn screening programs: the cystic fibrosis newborn screening experience in the United States. J Pediatr. 2005;146:668–674. [DOI] [PubMed] [Google Scholar]
- 3.Sarles J, Berthezene P, Le Louarn C, et al. Combining immunoreactive trypsinogen and pancreatitis-associated protein assays, a method of newborn screening for cystic fibrosis that avoids DNA analysis. J Pediatr. 2005;147:302–305. [DOI] [PubMed] [Google Scholar]