Newborn screening for genetic disorders.

Newborn screening has become an integral part of the evaluation of more than 4 million newborns a year in the United States and of most newborns in industrialized countries and many in developing countries. Because the term "newborn screening" refers to many procedures performed in a nursery such as screening for hearing loss or congenital heart disease, this discussion is limited to screening for genetic or congenital disorders with blood spotted on filter paper cards. This discussion reflects primarily the experiences and current status of NBS programs in the United States.