Newborn screening: What's new?

Screening newborn infants for inborn errors of metabolism (IEM) began in the United States almost 50 years ago with the introduction of testing for phenylketonuria (PKU) in the state of Maine. As the understanding of genetics and metabolism grew, and as testing methodologies became more automated and sensitive, both the number of states performing newborn screening (NBS) and the number of disorders for which patients can be screened began to grow. During the 1990s and the first decade of the 2000s, a new technology was introduced called tandem mass spectrometry (MS/MS) into the clinical laboratory and NBS arenas, which spurred the growth of screening to include as many as 30 disorders by almost all 50 states and Washington, DC. This technology gave laboratories the ability to rapidly and accurately test for multiple IEM simultaneously. Newborn screening programs became an integral part of assessing the health and well-being of every infant born in the United States.