Kids Home > Newborn PKU Screening

Can the Newborn PKU Test Be Done Too Soon?

Many states (and many healthcare providers) recommend or even require that two PKU tests be done: one shortly after birth, and one a few days later. The logic behind the two-test approach is as follows:
  • The baby needs to be consuming phenylalanine from formula or breast milk in order for the test to be accurate. If the baby isn't yet consuming protein because the mother's milk hasn't yet come in, some cases of PKU may be missed by the test.
  • Many babies go home within a day of delivery, not allowing for an in-hospital PKU test after the milk has come in.
  • The later test is considered more reliable, but the earlier, in-hospital test is done because there is no guarantee that the babies will ever come back to have the second test.
Studies seem to suggest that the PKU test is very reliable even when performed very early after birth. Research shows that colostrum contains a high level of phenylalanine, so the worries about a mother's milk not coming in are largely unfounded. Now, many states simply require the one in-hospital test. Nonetheless, if you live in a state that requires two PKU tests, your baby will need both of them.
If your baby tests positive initially, be aware that there is a chance of a false positive. Further tests are necessary to confirm the initial result.

Can I Opt Out of PKU Screening?

In some states, you can opt out of PKU screening, typically if you give religious reasons for doing so. In almost all states, the test (along with other newborn screening) will be performed without your consent or approval, so you'll need to find out ahead of time how to opt out and make sure everybody at the hospital knows that you've opted out.
Why would a parent want to opt out of PKU screening? There is some concern that participating in newborn screening will somehow include your baby in a DNA database that could someday be used for undesirable or sinister purposes. In a highly publicized case in 2010, Texas parents sued the state and a university involved for secretly storing and using the blood samples for research purposes without the consent of the parents.
This case stirred up quite a bit of controversy, for good reason. PKU screening is mandated by law in order to help protect babies; requiring that babies be screened but then keeping the blood sample after the screening and using it for other purposes, without consent, goes beyond the intent of the screening laws.
Several states now require that the blood samples be destroyed after a certain period of time instead of being stored indefinitely. If you are worried about this, find out the protocol for newborn blood spot storage and usage in your state. You may even be able to request that your baby's blood spot be destroyed sooner than usual.
If you are concerned with the storage and use of DNA from newborn screenings in your state, we suggest that you do not opt out of screening for the sake of your baby's health, but instead take up the issue with your lawmakers so that all babies can benefit from newborn screenings without being exposed to the privacy invasion of inclusion in DNA databases without consent.
Written by/reviewed by:
Last reviewed by: Arthur Schoenstadt, MD
Last updated/reviewed:
List of references (click here):
Other Articles in This eMedTV Presentation




Related Channels

eMedTV Links
Copyright © 2006-2019 Clinaero, Inc.

eMedTV serves only as an informational resource. This site does not dispense medical advice or advice of any kind. Site users seeking medical advice about their specific situation should consult with their own physician. Click Terms of Use for more information.

This site complies with the HONcode standard for trustworthy health information:
verify here.