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Risk Factor Screening Process

Key steps

  • Screening for cytomegalovirus (CMV) and genetic risk factors for permanent hearing loss (PHL) is offered for all babies at the time of the newborn hearing screen or when it is scheduled.
    • As of March 26, 2020, all babies are screened for hearing loss risk factors without the need for additional consent through the Infant Hearing Program. This temporary change is related to disruptions to hearing screening during the pandemic. 
  • Risk factor screening uses the dried blood spot sample collected for routine newborn screening to look for CMV and some common variants in the hearing loss genes called GJB2 and SLC26A4
  • Testing takes 1-2 weeks to complete, and results are sent to the Infant Hearing Program. 
  • Babies who screen positive for CMV or genetic risk factors for PHL will be contacted by Newborn Screening Ontario or their primary care provider to discuss the results and recommended follow-up. 


In light of the COVID-19 pandemic and discontinuation of non-essential services, the Infant Hearing Program (IHP) is postponing all audiometric hearing screening and is temporarily unable to obtain consent for risk factor screening for PHL. After careful review by the Ontario Ministries of Health (MOH) and Children Community and Social Services (MCCSS), a decision was made to continue with the risk factor screening program. All specimens from babies born on or after March 26, 2020 will be screened for CMV and genetic risk factors for PHL without the need for additional consent by the IHP. Screen positive results continue to be referred for medical and audiologic follow-up. These are temporary measures, and we will revert to our original consent practice as soon as the IHP returns to regular operations. Please contact NSO if you have any questions.

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