In 1961, Robert Guthrie, a doctor and bacterial scientist at the University of Buffalo Children's Hospital, developed a way to test whether newborn babies have phenylketonuria (PKU), an inability to digest the amino acid phenylalanine. He tested for the presence of excess phenylalanine in the blood by seeing whether newborns' blood specimens encouraged the growth of a bacterial strain that requires a phenylalanine supplement to grow. Excess phenylalanine in the body poisons the nervous system and causes mental retardation. But if babies with PKU are identified early, they can go on a diet that avoids the amino acid phenylalanine and evade almost all symptoms of the condition. Mass screening for PKU became routine among newborns a few years after Guthrie's proposal; by 1967, 37 states in the United States had laws requiring screening.
Today, newborns throughout much of the world are screened not just for PKU, but also for hypothyroidism and other inborn disorders where an early warning can be used to prevent dire effects.
Guthrie, R. Blood Screening for Phenylketonuria. JAMA, 178:863. 1961.
Last Reviewed: April 26, 2013