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Traditional newborn dried blood spot screening (NDBS) has expanded in recent years to include upwards of 50 different conditions in many states. Once the screening tests are complete, the residual blood specimens (RBSs) that remain are most often available for quality assurance and public health research. The articles by Botkin et al1 and Bombard et al2 contained in this issue of Pediatrics investigate the attitudes of parents in both the United States ( n = 3855) and Canada ( n = 66) toward program policies that allow for the possible storage and secondary use of RBSs. Figure 1 illustrates the variability in the United States regarding the length of time RBSs are currently stored. Currently, 14 programs save RBSs for ≥21 years, and these programs serve ∼45% of all US births. Although the need for RBSs for laboratory quality assurance, which may include long-term needs, is generally understood (and accepted), the way in which programs disclose (or fail to disclose) information about these uses and the manner by which parents may choose to opt in or out of RBS storage and/or potential research uses are the subject of much discussion and controversy. FIGURE 1 Storage time for RBSs in … Address correspondence to Bradford L. Therrell, Jr, MS, PhD, National Newborn Screening and Genetics Resource Center, 1912 W. Anderson Lane #210, Austin, TX 78757. E-mail: therrell{at}uthscsa.edu

We conducted a structured telephone survey of state public health laboratory directors of neonatal screening programs to determine the extent of the problem of missed cases of phenylketonuria (PKU) and congenital hypothyroidism. A total of 76 missed cases were reported—43 PKU and 33 congenital hypothyroidism. We looked at the following characteristics of the missed cases: the stage at which the miss occurred, which included specimen collection, laboratory procedures, or follow-up; the size of the program; the type of screening program; the age of the infant at the time of screening; and any legal action that resulted from the miss. The 76 missed cases probably represent an underascertainment of the true number, yet we believe that our data provide an overview of some of the problems associated with mass neonatal screening. There was one missed case of PKU for every 70 cases detected, and one missed case of congenital hypothyroidism for every 120 cases detected; in other words, two congenital hypothyroidism cases were missed for every 1 million infants screened. Regarding the stage of screening in which the miss occurred, 14% occurred during specimen collection, 45% during the laboratory procedures stage, 16% during follow-up, 11% were the result of biologic variation, and in 14% the stage could not be identified. We conclude that neonatal screening programs have been highly successful but that there may be additional safeguards to be developed, tested, and implemented when practical.