Phenylalanine Products Guthrie Card: Blood is taken by heal stick from newborns and spotted onto an absorbent paper card that is sent to a diagnostic laboratory, where tests for various disorders are performed.


The Guthrie test, also called the PKU test, is a diagnostic tool to test infants for phenylketonuria a few days after birth. Robert Guthrie invented the test in 1962 in Buffalo, New York. After his first success testing for PKU, Guthrie developed paper cards, called Guthrie Cards, which are thick, absorbent papers each with a metal blade to puncture an infant's heel and places for spotting infant blood. The New York State Newborn Screening Program effectively identifies babies with certain disorders and is required for all newborns born in New York unless the parents confirm, in writing, that they have a religious objection. The blood-spotted Guthrie Card is sent to the New York State Testing Laboratories in Albany, where the testing is performed; the blood is used to screen for approximately 50 different disorders, most of which are genetic disorders.