Frequently Asked Questions
What is newborn screening?
•
Newborn screening is the process of testing of babies shortly after birth for treatable
diseases that are not usually apparent in the newborn period.
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Early detection of these diseases through newborn screening prevents serious health
problems and can even save lives.
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Using a heelprick test, a small amount of blood is collected from all babies shortly after
birth. This blood is sent to Newborn Screening Ontario (NSO) where it is tested for 29
diseases. With these diseases, early diagnosis is the key to effective treatment.
What is Severe Combined Immune Deficiency (SCID)?
Newborns with SCID do not have an immune system to fight off infections. They appear
healthy at birth, but develop life-threatening infections within the first few months of life.
Without a diagnosis, the infants are repeatedly hospitalized and often die before their first
birthday. Usually the diagnosis of SCID is either missed or delayed until the age of 6-12
months of age, after patients suffer from severe and recurrent infections and sometimes
irreversible damage to organs such as the lungs.
Why screen newborns for SCID?
Newborns with SCID do not usually have any signs of the disease, but eventually develop lifethreatening infections. Screening babies at birth for SCID allows the disease to be identified
before they get infections, so that early treatment can begin.
Is SCID curable? What is the treatment?
SCID can be cured by giving a baby a new working immune system through a bone marrow
transplant. Other treatments like enzyme replacement therapy or gene therapy may be
possible for some types of SCID. Transplants in early infancy offer the best outcome. Any of
these treatments should be initiated before a baby begins to suffer serious infections.
401 Smyth Road
Ottawa Ontario K1H 8L1
Toll-free: 1-877-NBS-8330 / Local: (613)738-3222
www.newbornscreening.on.ca
@NBS_Ontario
How is the screening test for SCID performed?
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SCID screening is performed using the same blood samples that are collected for
routine newborn screening.
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NSO uses a DNA test (real-time polymerase chain reaction) to measure T-cell receptor
excision circles (TRECs), which are small pieces of DNA made during the maturation of
the T-cells of the immune system. Newborns with SCID lack or have low TRECs.
What are the possible results of newborn screening for SCID?
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A “screen negative” result means that a baby is at reduced risk for SCID and no followup testing is necessary.
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A “screen positive” result means that a baby is at increased risk for SCID and follow-up
testing is necessary to determine whether he or she truly has the disease.
•
Sometimes, screening samples are not satisfactory for testing and a repeat sample is
required to complete screening for a baby. This does NOT mean that a baby has a
health problem.
What happens when a baby screens positive for SCID?
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Babies who screen positive for SCID are referred by NSO to specialists at a Regional
Newborn Screening Treatment centre for follow-up diagnostic testing to determine
whether or not they have SCID.
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Parents are informed of a positive newborn screening result for SCID either by their
baby’s primary health care provider or a health care professional from the closest
Regional Newborn Screening Treatment Centre.
Where are the Regional Newborn Screening Treatment Centres located?
Regional Newborn Screening Centres are located at the following hospitals:
o The Children’s Hospital of Eastern Ontario (Ottawa)
o Kingston General Hospital
401 Smyth Road
Ottawa Ontario K1H 8L1
Toll-free: 1-877-NBS-8330 / Local: (613)738-3222
www.newbornscreening.on.ca
@NBS_Ontario
o The Hospital for Sick Children (Toronto)
o Hamilton Health Sciences
o London Health Sciences Centre
Babies from northwestern Ontario who screen positive for SCID are referred to the Winnipeg
Regional Health Authority for follow-up testing.
Are there false positive results with SCID newborn screening?
As with any screening test, the test for SCID can produce false positive results. It is estimated
that approximately 50 infants in Ontario will screen positive each year for SCID, requiring
follow-up investigations, and about 5-10 of them will ultimately be diagnosed with the
disease.
Are there false negative results with SCID newborn screening?
The state of Wisconsin was the first to begin newborn screening for SCID, and a report from
their newborn screening program indicates that no cases of SCID have been missed.*
However, as with any screening test, newborn screening for SCID may miss a baby with the
disease. If a baby has symptoms of SCID, diagnostic testing for the disease is recommended,
even if the baby had a negative result for SCID on the newborn screen.
How do parents find out their baby’s newborn screening results?
Newborn screening results are routinely sent to the hospital, doctor and/or midwifery
practice that collected the sample. Newborn Screening Ontario does not release results
directly to parents or guardians. If parents would like a copy of their baby’s results, they can
ask their baby's health care provider or the hospital where their baby was born.
What happens if a baby really has SCID?
If follow-up testing is positive, immunologists begin treatment. Bone marrow transplantation
is most effective as it gives children an immune system that is able to fight infections.
Depending on the specific type of SCID, other treatments may be considered. Most babies
diagnosed with SCID will be referred to Dr. Chaim Roifman, a Pediatric Immunologist and
Scientist in the Division of Immunology/Allergy at The Hospital for Sick Children in Toronto,
Ontario and a Professor of Pediatrics and Immunology and the University of Toronto.
401 Smyth Road
Ottawa Ontario K1H 8L1
Toll-free: 1-877-NBS-8330 / Local: (613)738-3222
www.newbornscreening.on.ca
@NBS_Ontario
What other jurisdictions screen for SCID?
Ontario is the only Canadian province currently screening newborns for SCID. In 2008,
Wisconsin was the first jurisdiction in the world to begin SCID newborn screening. Several
other US states have implemented SCID screening; most recently Pennsylvania and Utah. No
newborn screening programs outside of North America test for SCID.
How was SCID added to Ontario’s newborn screening panel?
Immunodeficiency Canada, with the support of several families who have had babies with
SCID, advocated for SCID to be added to Ontario's newborn screening panel. An in-depth
analysis was performed by the Newborn and Childhood Screening Subcommittee of the
Ontario Maternal-Child Screening Committee. In August 2012, this was presented to the
Ontario Ministry of Health and Long Term Care (MOHLTC), along with an implementation
proposal from NSO. After a detailed review, the MOHLTC approved and committed funding
to NSO to begin SCID screening.
*Verbsky J, Thakar M and Routes J. The Wisconsin approach to newborn screening for severe combined immune
deficiency. J Allergy Clin Immunol 2012; 129: 622-627.
401 Smyth Road
Ottawa Ontario K1H 8L1
Toll-free: 1-877-NBS-8330 / Local: (613)738-3222
www.newbornscreening.on.ca
@NBS_Ontario