Current status of neonatal screening for congenital adrenal hyperplasia.

Greater than 7.5 million newborns have been screened for 21-hydroxylase deficiency congenital adrenal hyperplasia (CAH) worldwide. As a result of such screening efforts, neonatal screening for CAH has proven to be highly reliable and has benefited countless numbers of affected newborns with classic 21-hydroxylase deficiency by contributing to the early diagnosis of the disorder. The screening process, however, is less reliable among low-birth-weight or preterm infants, and recent studies show that newly established normative reference levels based on birth weight or gestational age may minimize false-positive rates and improve the efficacy of newborn screening for CAH, particularly in low-birth-weight newborns.