Newborn screening

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Learn about the different types of newborn screening and what to do if your baby has positive newborn screening results.

Key points

  • Newborn screening includes tests done shortly after birth that look for treatable health conditions.
  • Babies who are diagnosed through newborn screening and start treatment early have better long-term health outcomes.
  • In Ontario, newborn screening includes four parts: a blood test (the “heel prick”), a hearing test, a blood oxygen level test (pulse oximetry) and biliary atresia screening (stool colour monitoring).
  • Positive newborn screening results mean that your baby may have a health condition. Further assessment is needed to determine whether your baby has a condition. Negative newborn screening results mean that your baby’s chance of having the conditions screened for is low.

What is newborn screening?

Newborn screening includes tests done shortly after birth that look for treatable diseases. Newborn screening should be offered to every baby. It is not mandatory but is very strongly recommended. Newborn screening is important for all babies, even healthy babies, because these conditions usually show no signs or symptoms in the newborn period. Through newborn screening, early diagnosis and treatment can improve the health and development of your child and may be lifesaving.

What tests are done?

In Canada, each province decides which conditions they screen for and how screening will be done. In Ontario, newborn screening is coordinated by Newborn Screening Ontario (NSO), and includes four parts:

  • A newborn screening blood spot card (sometimes called the “heel prick test”)
  • A hearing screening (managed by Ontario’s Infant Hearing Program)
  • A critical congenital heart disease (CCHD) screening
  • Biliary atresia screening

If you have questions about your baby’s newborn screening test, contact your prenatal health-care provider or family doctor.

Newborn screening blood spot card

Every baby in Ontario should be offered a newborn screening blood spot test 24–48 hours after birth. This is sometimes called the “heel prick” test. A health-care provider will collect a small sample of blood from your baby’s foot and place the blood on a special type of paper called a “blood spot card”.

In Ontario, newborn screening started in 1965. Now, Newborn Screening Ontario tests for about 30 different health conditions. These conditions are included in newborn screening because, if they are detected, treatments are available that are known to improve the health and/or developmental outcomes of your child.

Newborn hearing screening

Every newborn in Ontario should also be offered newborn hearing screening through the Ministry of Children, Community and Social Services’ (MCCSS) Infant Hearing Program (IHP). Newborn hearing screening identifies babies who need more in-depth hearing testing and/or medical follow-up.

Newborn hearing screening involves two parts:

  1. measuring your baby’s brain response to sounds.
  2. using the newborn screening blood spot card to test for hearing loss risk factors.

Hearing loss risk factors that are tested include both genetic risk factors and congenital cytomegalovirus (cCMV). Cytomegalovirus (CMV) is a common virus that, if passed from the birthing parent to your baby, can cause hearing loss and/or developmental concerns. CMV infection is often mild, and most birthing parents and babies are asymptomatic. A small percentage of exposed babies will show problems related to CMV.

Critical congenital heart disease screening

Critical congenital heart diseases (CCHDs) are structural differences in babies’ hearts that often require surgery or intervention early in life. CCHD screening is done by measuring the level of oxygen in your baby’s blood using a test called pulse oximetry, where a small plastic probe is wrapped around your baby's hand and foot. This is a “point of care” test, meaning that the test is done at the bedside and results are available immediately. CCHD screening is usually performed 24–48 hours after birth.

Biliary atresia screening

Biliary atresia is a rare but serious disease of the liver, where bile is unable to leave the liver. Bile is a digestive fluid that is made in the liver and empties into the intestine. Bile is what makes stool (poop) darker in colour. When infants have biliary atresia, the bile builds up in their liver, leading to pale stools and eventual liver damage. Screening for biliary atresia is done by monitoring your baby's stool colour after birth using an Infant Stool Colour Card, which your birth hospital or midwife should have provided you with.

For more information about stool monitoring and biliary atresia, please see the article, Biliary atresia.

Newborn screening results

A negative newborn screening result means that the risk for the conditions being tested is low, and usually this also means no further testing is needed. It is important to know that newborn screening is not a diagnostic test. If your doctor suspects your baby may have one of the conditions that can be detected through newborn screening, further testing may still be needed, even if your baby’s newborn screening results are negative.

A positive newborn screening result means that your baby has an increased risk for the condition(s) being tested, and may have a condition. However, it is also possible they may not. A positive newborn screening result needs to be followed up with diagnostic testing, which aims to confirm or rule out the condition(s).

If any of your baby’s newborn screening tests are positive, you will be contacted by a health-care provider who will inform you of the results and guide you on the next steps.

Your baby’s newborn screening results are sent to the health-care provider who ordered the newborn screening tests. This is usually a doctor at the hospital where your baby was born, or your midwife. To access your baby’s newborn screening results, your health-care provider can contact Newborn Screening Ontario. Parents can also request their child’s screening results themselves.

Last updated: July 21st 2023