Impact:

Phenylketonuria (PKU) is a genetic disorder characterized by an inability of the body to break down the amino acid phenylalanine. Recognizing that the earlier treatment begins for PKU, the better the prognosis for intellectual growth, Guthrie developed a way to collect discs of whole blood from infants: sticking the baby’s heel and blotting the emerging drops of blood with filter paper. Hospitals were able to quickly and inexpensively implement PKU screening on a large scale, and in time, the filter test—which is estimated to have spared 300,000 children from the effects of mental disabilities—came to be used by all 50 states to screen for PKU. Furthermore, Guthrie’s dried-blood spot testing method spread to almost every field involving blood collection and has made possible the multiple newborn screening routinely conducted today.