Risk Factor Screening FAQ

• Risk factor screening for permanent hearing loss (PHL) is offered to all babies who participate in hearing screening.
• This screening is offered at the time infant hearing screening is done, or when it is booked. 
• NSO uses the dried blood spot sample already collected by the hospital or midwife for routine newborn screening (the heel prick test) to do this testing, which looks for cytomegalovirus (CMV) infection and some common genetic risk factors for PHL.
• Babies with these risk factors have a higher chance of having PHL at birth or developing it in childhood.
• When found through screening, these babies can be referred for the appropriate audiologic and medical follow-up. 

Risk factor screening for permanent hearing loss (PHL) looks for babies who are at increased risk to have PHL at birth, or to develop it in early childhood. Babies with risk factors for PHL identified through screening are offered a diagnostic audiologic assessment with an IHP audiologist. The IHP offers ongoing monitoring if PHL is not identified. The goal of risk factor screening for PHL is to find babies with PHL as early as possible. This allows the IHP to provide the supports and services they need to support the development of language and communication.

There is no right or wrong choice when it comes to a parent or guardian’s decision about risk factor screening for permanent hearing loss (PHL). Some may decide not to have their baby screened. 

If a baby has risk factor screening, parents could learn that their baby has a congenital cytomegalovirus CMV (cCMV) infection. Most babies with cCMV will not develop any health problems related to the infection. Some babies, though, will develop permanent health issues, most commonly hearing loss. Currently, there isn't a good way of knowing if or when a baby with cCMV will develop hearing loss. This means that some babies with cCMV may get extra monitoring and checkups and no health issues related to the infection would be found. 

If a baby has risk factor screening, parents could learn that their baby has genetic risk factors for PHL. Babies with these risk factors have a high chance of having PHL at birth or of developing it in early childhood. Some babies with a positive genetic risk factor screening will need to have their hearing checked more often in early childhood. A small number of babies with a positive genetic risk factor screening result never develop PHL.

Some parents might feel that the extra monitoring involved when a baby has a positive risk factor screen is reassuring, because it would allow hearing loss to be found as early as possible. Other parents might feel that the extra monitoring could make them more worried about their baby’s chance to develop hearing loss.

No. Newborn screening is considered the standard of care in Ontario. Most babies born in Ontario get a newborn screen to check for the potential of a variety of rare, but treatable diseases. Risk factor screening for PHL uses the same blood sample that was collected for newborn screening. Parental/guardian consent is required. Consent is obtained at the time hearing screening occurs, or when it is booked. Risk factor screening for PHL is only available to babies who have hearing screening through the Infant Hearing Program (IHP).

In Ontario, most babies have a newborn screening blood sample collected within 24-48 hours after birth. NSO also contacts the birthing hospital and/or midwife about one week after a baby’s birth to follow-up on any babies who may not have had a newborn screening sample collected yet. This helps ensure that no babies whose parents wished them to be screened are missed.

If you are concerned that a sample may not have been collected for your baby, please call us at 1-613-738-3222. While NSO will not release screening results to parents by phone, we can confirm if we received a sample. We can also arrange to send results to the baby’s doctor.

If you declined risk factor screening for PHL for your baby and change your mind, contact your regional Infant Hearing Program.

If you consented to risk factor screening for PHL for your baby but change your mind, contact NSO for information about next steps. Once the risk factor screen is requested, results are usually available within 1-2 days.  Depending upon how much time has passed, it is possible that testing was already completed.  

No. Risk factor screening for PHL involves using the newborn screening sample for testing. If newborn screening was not performed, for example if the baby’s parent or guardian declined, NSO would not have a dried blood spot sample to be able to perform the risk factor screening for PHL.  

If your baby was born outside of Ontario, contact the Infant Hearing Program in your region and/or speak to your baby’s health care provider to learn if your baby can have hearing screening. Risk factor screening for PHL is only available to babies whose parents/guardians consent to hearing screening in Ontario.

If a baby is over 3 weeks old when they arrive in Ontario, risk factor screening for PHL will only include screening for genetic risk factors. Screening for congenital Cytomegalovirus (cCMV) infection will not be performed. The test for cCMV is not reliable when using a dried blood sample collected from a baby who is over 3 weeks old.

Risk factor screening for PHL is only available to babies whose parents/guardians consent to infant hearing screening in Ontario. Contact the Infant Hearing Program in your region or speak to your baby’s health care provider to learn if hearing screening is available.

Screening results should be available 1-2 weeks after NSO receives the request for testing. NSO sends results to the Infant Hearing Program in the region in which the baby was screened. NSO can also send results to a baby’s health care provider upon request.  

Negative screening results mean that:

• cCMV was not detected
• The common variants tested in the GJB2 and SLC26A4 genes were not detected
  • Negative genetic risk factor screening results do not provide information regarding a child’s carrier status for the variants tested. Carrier results are available by request from NSO.

• The risk factor screen cannot rule out cCMV infection as the sensitivity of the test is approximately 80%
• • An infant could have a cCMV infection that is not detected through the risk factor screen (i.e. false negative)
  • If an infant has concerns suggestive of possible cCMV infection, diagnostic testing should be considered
  • Please contact NSO about any infant in your care who has a suspected or confirmed cCMV infection and negative risk factor screening results.
• The risk factor screen looks for some, but not all, variants in the GJB2 and SLC26A4 genes
  • An infant may have other variants in these genes that are not detected through the risk factor screen
  • If an infant is at high risk of childhood-onset PHL based on family history, a referral to your local Genetics clinic should be considered

Screen negative results should be interpreted along with the results of a child’s IHP hearing screen and/or audiology assessment. Please contact your local IHP Lead Agency to request results of a child’s hearing screen or audiology assessment.

• A child who passes IHP hearing screening and has a negative result on their risk factor screen does not require any further follow-up unless additional risk factors were identified by the IHP.  If any concerns arise in the future regarding a child’s hearing, parents/guardians should follow-up with their child’s health care provider.
• A child who has received a refer result on IHP hearing screening and has a negative result on their risk factor screen should continue to their next step in the IHP screening pathway (e.g. community screen or audiology assessment).
• A child who has not had their hearing screened - parents/guardians should follow-up with the Infant Hearing Program in their region for recommendations regarding hearing screening. Negative risk factor screening results should be interpreted with caution and do not rule out the possibility of hearing loss or risk for hearing loss.
• A child with confirmed PHL will be offered services and support through the IHP. A negative risk factor screening result means that the screen did not identify a cause for the child’s hearing loss.   
  • Referrals to Otolaryngology and Genetics, and additional investigations to identify the potential etiology of a child’s hearing loss should be considered.
  • NSO can provide additional interpretation, and potentially further testing, for children who have PHL and negative risk factor screening results. Please contact NSO for more details.

Please view our guide for the interpretation of negative risk factor screening results for PHL.

When a parent or legal guardian provides consent for a baby to have risk factor screening for Permanent Hearing Loss (PHL), the Infant Hearing Program (IHP) requests the testing be performed by Newborn Screening Ontario (NSO). If NSO has a suitable sample, it will be tested. However, sometimes a suitable sample is not available for testing. 

1. No sample can be identified at NSO: this could be because a dried blood spot sample was never obtained or the personal health identifiers provided were insufficient or did not match (for example, no health card number provided and a change of name). A newborn screening sample can still be taken. Please note that testing for cytomegalovirus (CMV) is not reliable if the baby is older than 3 weeks of age when the sample is collected. In this circumstance, genetic risk factor screening can still be performed. 
2. A sample is located at NSO but there is not enough sample remaining to perform the tests. An additional newborn screening sample can still be taken. Please note that testing for cytomegalovirus (CMV) is not reliable if the baby is older than 3 weeks of age when the sample is collected. In this circumstance, genetic risk factor screening can still be performed on the additional sample that is received. 
3. A sample is located at NSO but was collected from a baby at greater than 3 weeks of age. Testing for cytomegalovirus (CMV) is not reliable if the baby is older than 3 weeks of age when the sample is collected and will not be performed. Genetic risk factor screening can still be done. 

In these scenarios a report will be sent to the IHP informing them that NSO was unable to test a sample.