Before revision: The blood of a two-week-old infant is collected for a Phenylketonuria, or PKU, screening The neonatal heel prick or Guthrie test is a screening test done on newborns.
After revision: The blood of a two-week-old infant is collected for a Phenylketonuria, or PKU, screening The neonatal heel prick is a blood collection procedure done on newborns.