Key Takeaways

Please use the term "newborn screen". The term "PKU test" is outdated and inaccurate.
PKU (or phenylketonuria) is only one of the diseases targeted by newborn screening. View the current list of the diseases screened here.

About 250 babies each year are identified to have a disease targeted by newborn screening. The diseases may individually be rare, but collectively impact around 1 in 600 babies born.
The diseases targeted by newborn screening are not usually apparent at birth, and most affected infants have no family history of the disease. It is therefore very important that newborn screening is offered for every baby.

Early discharge (<24 hours)
- Infants discharged prior to 24 hours of age should have a dried blood spot sample taken prior to discharge, if possible. Parents/guardians may also choose to defer screening. Regardless, please inform parents of the need and process for to have the repeat screen collected within 5 days.
- Pulse oximetry screening for critical congenital heart disease (CCHD) can only be performed after 24 hours of age. Ensure the parents know they need to return for CCHD screening.
Hospital transfers
- If an infant is transferred to another hospital, ensure there is communication between hospitals regarding the responsibility for performing newborn screening.

If undetected and untreated, these diseases may cause intellectual deficits, serious health problems, or even death.
Early detection and treatment can greatly improve the outcome for affected infants and sometimes even save their life. For example, infants with phenylketonuria (PKU) and congenital hypothyroidism (CH) irretrievably lose significant cognitive function if phenylalanine and thyroid stimulating hormone (TSH), respectively, are not under control by three weeks of age.

A "positive" newborn screening result does not mean an infant is affected with a disease. Diagnostic testing must be done to confirm or rule out a disease.
A "negative" newborn screening results screen does not rule out a disease. Infants at risk for a disease screened based on clinical presentation or family history should have the appropriate diagnostic evaluation immediately.

Newborn screening is considered standard of care and is strongly recommended for all babies.
Thoroughly explain newborn screening to all parents/guardians. If they do not consent to testing, it is extremely important to document the refusal in the infant’s records or to use the decline form included with the newborn screening card.

The submitting institution or midwifery practice that collected the initial dried blood spot sample is responsible for ensuring the repeat sample is collected, even if the infant has been discharged.
Delays in obtaining a repeat sample can lead to delayed diagnosis and serious health problems in affected infants.

All requested information is essential for accurate interpretation and follow-up of results.
Incorrect or missing information can lead to false positive results and unnecessary testing for healthy infants.

NSO is committed to maintaining the privacy and confidentiality of the health information and dried blood spot samples it receives. Click here to learn about privacy and confidentiality at NSO.
Some parents/guardians may have concerns about the use of their child’s health information or the secondary use of their dried blood spot sample. In some cases, parents/guardians request destruction or release of their sample from NSO. Click here for information on the storage and secondary use of dried blood spot samples.

Children’s Hospital of Eastern Ontario
415 Smyth Road
Ottawa, Ontario K1H 8M8

Toll-Free: 1-877-627-8330
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Fax: (613) 738-0853