Navigating the maze of newborn screening.

Newborn screening tests are obtained for all live births in the United States in an effort to identify newborns affected with, or at risk for, various genetic and metabolic diseases. This screening began in the early 1960s with an inexpensive screening test for phenylketonuria (PKU), but the introduction of new technology in the 1990s using tandem mass spectrometry provided the means to screen for over 30 additional metabolic disorders. Newborn-screening programs are state funded and operated, and many factors affect whether certain conditions are included in a state's screening program, including how severe the condition would be if left untreated, the prevalence of that condition in the state's population, and whether there is a treatment available that would improve the course of illness.