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Newborn Screening Ontario
About Screening

What is Screening?

Newborn screening is a test done shortly after birth to test for treatable diseases that usually show no symptoms in the newborn period.

Using a heel-prick, a small amount of blood is collected from all babies shortly after birth. In Ontario, this blood is sent to Newborn Screening Ontario (NSO) in Ottawa where it is tested for serious diseases. With these diseases, early diagnosis is the key to effective treatment.

Screening for Critical Congenital Heart Disease (CCHD) is also offered to babies in Ontario. This is a quick and painless test called pulse oximetry that measures the level of oxygen in a baby’s blood. This test is done at the bedside and results are available right away.

The picture below explains why newborn screening is so important. Please click "More Detail" to learn more about any of the messages below.

Screening is Important

  • 1
    Every baby is at risk
    • Most babies are born healthy, but about 1 in 1000 babies will have one of the diseases the blood test screens for and about 3 in 1000 babies will have critical congenital heart disease (CCHD).
    • Babies with these diseases usually look healthy at birth and have no history of the disease in their family.
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  • 2
    The diseases are serious and could be life-threatening if not treated
    • Early detection of the diseases through newborn screening prevents serious health problems and can save lives.

    • The benefits of early detection and treatment made possible by newborn screening far outweigh the short term discomfort from a heel-prick test at birth.

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  • 3
    You can't tell by looking at a baby if he or she has one of the diseases
    • Most babies with the diseases screened look healthy at birth; newborn screening is important for every baby.
    • Newborn screening helps identify babies with these diseases before they get sick so they can get the treatment they need.
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  • 4
    There is usually no family history of the disease in a family
    • Babies with the diseases tested are usually born to healthy parents who do not have a family history of the disease. Newborn screening is therefore important for every baby.
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  • 5
    Parents will be notified if the baby needs more testing
    • Most babies have "screen negative" results and no more testing is needed. Newborn screening results are sent to the hospital or health care provider who took the newborn screening sample. Parents are not routinely contacted if the result is “screen negative". Critical Congenital Heart Disease (CCHD) screening results are available immediately.
    • Babies with a “screen positive” result need further evaluation and/or testing to tell if the baby has the disease or if the result was a “false positive.”
    • Some babies need a repeat newborn screen because the sample was not suitable for testing (e.g. not enough blood for the tests), or a repeat CCHD screen because the screen was not satisfactory. 
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