Phenylketonuria (PKU) Test
What To Think About
- When the PKU test is done within 24 hours of birth, there is a small chance that the test result will not be accurate (Reference false-negative Opens New Window or Reference false-positive Opens New Window). Your baby may need to be tested again. There is less chance of a false result if the test is done between 24 and 72 hours after birth.
- If your baby has PKU, he or she will need regular blood tests to check Reference phenylalanine Opens New Window levels. These tests may occur as often as once a week in your baby's first year and then once or twice a month throughout childhood.
- A blood test for phenylalanine may be done if you have PKU and plan to become pregnant. If you eat too much protein, you will have high levels of phenylalanine in your blood. If you become pregnant, the high levels of phenylalanine could cause your baby (fetus) to have Reference intellectual disability Opens New Window, even if your baby does not have PKU. It is important that everyone with PKU see a specialist for nutritional counseling. Phenylalanine levels should be below 6 mg/dL at least 3 months before you become pregnant. Recommended phenylalanine levels during pregnancy are 2 mg/dL to 6 mg/dL, and you should be tested at least once a week.
- A test for phenylalanine levels in urine may be done if your baby is now over 6 weeks of age and did not have a PKU blood test 2 to 3 days after birth. A PKU heel stick can be done up to 6 weeks of age and has better results than a urine test. A urine test may be done to check phenylalanine levels during treatment with low-protein foods.
- If your baby has PKU, a special low-protein diet is needed to prevent intellectual disability. Your baby will drink milk substitutes that do not contain phenylalanine. People with PKU need to stay on a low-protein diet for life to prevent problems.
|By:||Reference Healthwise Staff||Last Revised: Reference June 19, 2012|
|Medical Review:||Reference John Pope, MD - Pediatrics
Reference Chuck Norlin, MD - Pediatrics
© 1995-2011, Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.