Phenylketonuria (PKU) Test

PKU (Phenylketonuria) Screening

Why It Is Done

A phenylketonuria (PKU) test is done to see whether a newborn baby has the enzyme to use phenylalanine in his or her body.

It is important to test your baby for PKU soon after birth to prevent brain damage. Phenylalanine blood levels in a baby with PKU start to rise within 24 hours of drinking breast milk or formula. A PKU test done 2 to 3 days after birth will show whether your baby has PKU. Newborns in Canada are routinely tested for PKU within a few days after birth.

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Author:	Debby Golonka, MPH Ralph Poore	Last Updated: April 14, 2008
Medical Review:	Anne C. Poinier, MD - Internal Medicine Michael J. Sexton, MD - Pediatrics Thomas Emmett Francoeur, MDCM, CSPQ, FRCPC - Pediatrics
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