Newborn blood testing identifies almost all cases of phenylketonuria. All 50 states in the United States require newborns to be screened for PKU. Many other countries also routinely screen infants for PKU.
If you have PKU or a family history of it, your doctor may recommend screening tests before pregnancy or birth. It's possible to identify PKU carriers through a blood test.
Testing your baby after birth
A PKU test is done a day or two after your baby's birth. The test isn't done before the baby is 24 hours old or before the baby has ingested some protein in the diet to ensure accurate results.
- A nurse or lab technician collects a few drops of blood from your baby's heel or the bend in your baby's arm.
- A laboratory tests the blood sample for certain metabolic disorders, including PKU.
- If you don't deliver your baby in a hospital or are discharged soon after the birth, you may need to schedule a newborn screening with your pediatrician or family doctor.
If this test indicates your baby may have PKU:
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- Your baby may have additional tests to confirm the diagnosis, including more blood tests and urine tests
- You and your baby may undergo genetic testing to identify gene mutations
- Phenylketonuria. Genetics Home Reference. http://ghr.nlm.nih.gov/condition=phenylketonuria. Accessed Oct. 12, 2014.
- Greene CL, et al. National Institutes of Health (NIH) review of evidence in phenylalanine hydroxylase deficiency (phenylketonuria) and recommendations/guidelines for therapy from the American College of Medical Genetics (ACMG) and Genetics Metabolic Dietitians International (GMDI). Molecular Genetics and Metabolism. 2014;112:85.
- Camp KM, et al. Phenylketonuria Scientific Review Conference: State of the science and future research needs. Molecular Genetics and Metabolism. 2014;112:87.
- Ney DM, et al. Advances in the nutritional and pharmacological management of phenylketonuria. Current Opinion in Clinical Nutrition and Metabolic Care. 2014;17:61.
- Marcason W. Is there a standard meal plan for phenylketonuria (PKU)? Journal of the Academy of Nutrition and Dietetics. 2014;113:S1.
- Casey L. Caring for children with phenylketonuria. Canadian Family Physician. 2013;59:837.
- About phenylketonuria (PKU). National Human Genome Research Institute. http://www.genome.gov/25020037. Accessed Oct. 12, 2014.
- My PKU binder. National PKU Alliance. http://npkua.org/Education/MyPKUBinder.aspx. Accessed Oct. 21, 2014.
- Zeratsky KA (expert opinion). Mayo Clinic, Rochester, Minn. Nov. 5, 2014.
- Gavrilov DK (expert opinion). Mayo Clinic, Rochester, Minn. Nov. 10, 2014.