1) Testing done within days of birth to identify infants at increased risk for a specific genetic disorder so that treatment can begin as soon as possible; when a newborn screening result is positive, further diagnostic testing is usually required to confirm or specify the results and counseling is offered to educate the parents.

2) Newborn screening is testing performed on newborn babies to detect a wide variety of disorders. Typically, testing is performed on a blood sample obtained from a heel prick when the baby is two or three days old. In the United States, newborn screening is mandatory for several different genetic disorders, though the exact set of required tests differs from state to state.