Why is newborn screening performed during the first 72 hours of life?

Newborn screening is performed within the first 72 hours of life to facilitate the early detection and management of specific genetic and metabolic disorders.1

Many of these conditions, such as phenylketonuria (PKU), involve inborn errors of metabolism where the absence of a functional enzyme leads to the buildup of harmful substances or a deficiency in essential products. If left undetected, these disorders can cause severe, irreversible illness and brain damage.23

By identifying these conditions shortly after birth, medical professionals can implement early interventions—such as specialized diets or other treatments—that prevent the onset of symptoms and allow affected infants to grow and develop normally. This screening process, typically conducted via a neonatal heel prick, is a vital public health practice aimed at improving long-term health outcomes for newborns.231