Reflections on 50 years of newborn screening.

Newborn screening (NBS) began 50 years ago with the ability to screen for phenylketonuria from dried-blood spots and prevent long-term disability through dietary intervention. Now nearly all of the 4 million infants born in the United States are screened for a wide array of significant medical conditions by using dried-blood spots and pointof-care tests, leading to early diagnosis and treatment of more than 12 500 newborns each year. NBS is an unqualified public health success; it saves lives, prevents severe disability, and is a good use of limited health care dollars. NBS is not a test, but a complex system that includes the initial screen to identify infants with a high probability of having the condition, a follow-up diagnostic test to identify true cases, and the ongoing treatment of the condition. To make this system efficient and effective requires several key players, including public health, primary and specialty care providers, and families. On this anniversary of NBS, we would like to share our reflections on these 3 perspectives, acknowledging that they capture only some of the important considerations and advances in NBS.