A nurse is collecting a blood phenylketonuria (PKU) test for a newborn prior to discharge. The newborn's guardian asks the nurse what a positive PKU test would mean. Which of the following statements should the nurse make?

A positive finding indicates the inability to metabolize galactose.

A positive finding indicates the infant will have a slow metabolism.

A positive finding indicates an inability to metabolize certain amino acids.

A positive finding indicates an increased risk for neurologic anomalies.