http://www.marchofdimes.com/pnhec/298_834.asp
March of Dimes Birth Defects Foundation
All states screen newborns for certain metabolic birth defects. (Metabolic refers to chemical changes that take place within living cells.) These conditions cannot be seen in the newborn, but can cause physical problems, mental retardation and, in some cases, death. This publication discusses newborn screening tests, including what the tests look for and how they are done.